<PAGE>   1

                                 EXHIBIT 10.11
<PAGE>   2
                               SUBLEASE AGREEMENT


         SUBLEASE AGREEMENT ("Sublease") made and entered into this 31 day of
October 1997, by and between NATIONSBANK, N.A. ("Sublessor") and Mountain
National Bank ("Sublessee").

                              W I T N E S S E T H:

         WHEREAS, ROSWELL ROAD INVESTORS, LTD. ("Lessor"), and BANK SOUTH, N.A.,
a national banking association ("Bank South"), entered into that certain Amended
and Restated Lease Agreement, dated November 20, 1985, as amended December 18,
1985 ("Lease"), for the lease by Lessor to Lessee of certain space including the
Subleased Premises (as defined below);

         WHEREAS, Sublessor desires to sublease to Sublessee and Sublessee
desires to sublease from Sublessor all of the Subleased Premises, as hereinafter
set forth;

         WHEREAS, Sublessor is the successor by operation of law to Bank South;
and

         NOW, THEREFORE, the parties hereto, intending to be legally bound,
hereby agree as follows:

         1. SUBLEASED PREMISES. Sublessor hereby sublets to Sublessee, and
Sublessee hereby hires and takes from the Sublessor that certain space
("Subleased Premises"), called Unit 3 in the Lease and more particularly
described on Exhibit A attached hereto and made a part hereof, and consisting of
land and a free standing building containing approximately 3000 rentable square
feet located at 5340 Peachtree Industrial Blvd., Norcross, Georgia.

         2. TERM OF SUBLEASE. The term of this Sublease shall commence on the
earlier of (i) the date Sublessor delivers exclusive possession of the subleased
Premises to Sublessee or () October 31, 1998, and shall end on November 30, 2001
(the "Expiration Date") (or until such term shall sooner cease or expire as
hereinafter provided). Sublessor shall deliver exclusive possession of the
Subleased Premises to Sublessee immediately upon the execution and delivery of
this Sublease by both parties.

         3. THE LEASE.

         A. Sublessor represents and warrants that a complete and accurate copy
of the Lease is attached hereto as Exhibit B. Sublessor warrants and represents
that the Lease is in good standing and is in full force and effect in accordance
with its terms and there exists no default on the part of Sublessor, as "Tenant"
thereunder, or on the part of the "Lessor" thereunder, and that the Lease has
not been modified or amended in any respect, except as set forth in Exhibit B.
Sublessor represents and warrants that the commencement date under the Lease for
the Subleased Premises was December 18, 1985, and the expiration date under the
Lease for the
<PAGE>   3


Primary Term (as defined in the Lease) is midnight, November 30, 2011, pursuant
to the terms of the Lease.

         B. Sublessee acknowledges that it has reviewed and is familiar with all
of the terms, covenants and conditions of the Lease. Sublessee shall not be
bound by the terms of the exhibits to the Lease. AR of the terms, covenants and
conditions of the Lease, as applicable to the Subleased Premises are
incorporated herein and made a part hereof as if set forth herein at length,
except that "Lessor" shall be deemed to mean Sublessor and "Lessee" shall be
deemed to mean Sublessee; provided, however, that none of the provisions of
Section 3.6, Section 3.7 or Section 4.1 of the Lease shall apply to Sublessee.
Sublessee assumes and agrees, except as otherwise provided herein, to perform,
observe and comply with all of the terms, covenants and conditions on the
Lessee's part to be performed, observed and complied with under the Lease as the
same may or shall relate to the occupancy of the Subleased Premises, but only if
and to the extent the same relate to and accrue during the term of this
Sublease, and do not arise from the act or omission of Sublessor. Sublessor
agrees to indemnify Sublessee and hold Sublessee harmless from and against all
claims, losses or damages (including attorneys' fees) arising from Sublessor's
failure to perform or observe any of the terms or covenants of the Lease prior
to the commencement date of this Sublease. This indemnity shall survive the
expiration or earlier termination of this Sublease.

         C. This Sublease is expressly made subject and subordinate to all of
the terms and covenants of the Lease. So long as Sublessee performs all of its
covenants and obligations set forth in this Sublease, Sublessor agrees to pay
all accrued rent provided for under the Lease on or before the due date thereof,
and to otherwise perform all obligations thereunder that are not otherwise
required of the Sublessee in accordance to the terms of this Sublease. Sublessor
shall not commit or permit to be committed any act or omission that shall
violate or breach any term or condition of the Lease or cause the Lease to be
terminated. Sublessor agrees (i) not to amend, modify or otherwise change the
Lease in any way which would cause or result in the diminution of any rights of
the Sublessee under the Sublease; (ii) not to waive any rights of the "Lessee"
under the Lease; (iii) not to exercise any right or option to terminate the
Lease; and (iv) to give Sublessee immediately upon receipt copies of all notices
received by Sublessor and given by Lessor under the Lease, notices received from
any third party which relate to the Subleased Premises, and notices given by
Sublessor relating to the Lease. Any termination of the Lease or Sublessor's
right to the possession of the Subleased Premises shall result in a termination
of this Sublease unless Lessor elects to continue this Sublease in effect as a
direct lease between Lessor and Sublessee.

         4. OCCUPANCY AND ACCEPTANCE.

         A. Sublessee shall use and occupy the Subleased Premises solely for
retail banking and related uses and otherwise in compliance with all of the
terms of the Lease.

         B. Except as set forth herein, Sublessee covenants that it will occupy
the Subleased Premises in accordance with the terms of the Lease and will not
suffer to be done or omit to do


                                       2
<PAGE>   4

any act which may result in a violation of or a default under any of the terms
and conditions of the Lease, or render Sublessor liable for any charge or
expense. Sublessee further covenants and agrees to indemnify Sublessor against
and hold Sublessor harmless from any loss or liability arising out of, by reason
of, or resulting from, Sublessee's failure to perform or observe any of the
terms and conditions of the lease pertaining to the Subleased Premises. Any
other provision in this Sublease to the contrary notwithstanding, Sublessee
shall pay to Sublessor as additional rent any and all sums which Sublessor may
be required to pay to Lessor arising out of, by reason of, or resulting from
Sublessee's failure to perform or observe one or more of the terms and
conditions of the Lease pertaining to the Subleased Premises.

         (C) Sublessee agrees that Sublessor shall not be required to perform
any of the covenants or any of the obligations of Lessor under the Lease or
provide Sublessee any services or construct any improvements in the Subleased
Premises. Insofar as any of the covenants and obligations of Sublessor
thereunder are required to be performed under the Lease by Lessor thereunder,
Sublessee acknowledges that Sublessor shall be entitled to look to Lessor for
such performance. Sublessor shall take such commercially reasonable action as
may be appropriate under the circumstances, to secure such performance upon
Sublessee's written request therefor. Sublessee shall not conduct business
relating to the Subleased Premises directly with Lessor but shall deal with the
Lessor only through the Sublessor.

         (D) SUBLESSEE ACKNOWLEDGES AND AGREES THAT EXCEPT FOR ANY EXPRESS
REPRESENTATIONS OR WARRANTIES SET FORTH IN THIS SUBLEASE, SUBLESSOR HAS NOT
MADE, DOES NOT MAKE AND SPECIFICALLY NEGATES AND DISCLAIMS ANY REPRESENTATIONS,
WARRANTIES, PROMISES, COVENANTS, AGREEMENTS OR GUARANTIES OF ANY KIND OR
CHARACTER WHATSOEVER, WHETHER EXPRESS OR IMPLIED, ORAL OR WRITTEN, PAST, PRESENT
OR FUTURE, OF, AS TO, CONCERNING OR WITH RESPECT TO (A) THE VALUE, NATURE,
QUALITY OR CONDITION OF THE PROPERTY, INCLUDING, WITHOUT LIMITATION, THE WATER,
SOIL AND GEOLOGY; (B) THE INCOME TO BE DERIVED FROM THE PROPERTY; (C) THE
SUITABILITY OF THE PROPERTY FOR ANY AND ALL ACTIVITIES AND USES WHICH SUBLESSEE
OR ANYONE ELSE MAY CONDUCT THEREON; (D) THE COMPLIANCE OF OR BY THE PROPERTY OR
ITS OPERATION WITH ANY LAWS, RULES, ORDINANCES OR REGULATIONS OF ANY APPLICABLE
GOVERNMENTAL AUTHORITY OR BODY, (E) THE HABITABILITY, MERCHANTABILITY,
MARKETABILITY, PROFITABILITY OR FITNESS FOR A PARTICULAR PURPOSE OF THE
PROPERTY; (F) THE MANNER OR QUALITY OF THE CONSTRUCTION OF MATERIALS IF ANY,
INCORPORATED INTO THE PROPERTY; (G) THE MANNER, QUALITY, STATE OF REPAIR OR LACK
OF REPAIR OF THE PROPERTY, OR (H) ANY OTHER MATTER WITH RESPECT TO THE PROPERTY,
AND SPECIFICALLY, THAT SUBLESSOR HAS NOT MADE, DOES NOT MAKE AND SPECIFICALLY
DISCLAIMS ANY REPRESENTATIONS REGARDING COMPLIANCE WITH ANY ENVIRONMENTAL
PROTECTION, POLLUTION OR LAND USE LAWS, RULES, REGULATIONS, ORDERS OR EQUIPMENT,
INCLUDING SOLID WASTE, AS DEFINED BY THE U.S. ENVIRONMENTAL PROTECTION AGENCY
REGULATIONS AT



                                       3
<PAGE>   5


40 C.F.R., PART 261, OR THE DISPOSAL OR EXISTENCE, IN OR ON THE PROPERTY, OF ANY
HAZARDOUS SUBSTANCE AS DEFINED BY THE COMPREHENSIVE ENVIRONMENTAL RESPONSE
COMPENSATION AND LIABILITY ACT OF 1980, AS AMENDED, AND REGULATIONS PROMULGATED
THEREUNDER. SUBLESSEE FURTHER ACKNOWLEDGES AND AGREES THAT, HAVING BEEN GIVEN
THE OPPORTUNITY TO INSPECT THE PROPERTY, SUBLESSEE IS RELYING SOLELY ON ITS OWN
INVESTIGATION OF THE PROPERTY AND NOT ON ANY INFORMATION PROVIDED OR TO BE
PROVIDED BY SUBLESSOR. SUBLESSEE FURTHER ACKNOWLEDGES AND AGREES THAT ANY
INFORMATION PROVIDED OR TO BE PROVIDED WITH RESPECT TO THE PROPERTY WAS OBTAINED
FROM A VARIETY OF SOURCES AND THAT SUBLESSOR HAS NOT MADE ANY INDEPENDENT
INVESTIGATION OR VERIFICATION OF SUCH INFORMATION AND MAKES NO REPRESENTATIONS
AS TO THE ACCURACY OR COMPLETENESS OF SUCH INFORMATION. SUBLESSOR IS NOT LIABLE
OR BOUND IN ANY MANNER BY ANY VERBAL OR WRITTEN STATEMENTS, REPRESENTATIONS OR
INFORMATION PERTAINING TO THE PROPERTY, OR THE OPERATION THEREOF FURNISHED BY
ANY REAL ESTATE BROKER, AGENT, EMPLOYEE, SERVANT OR OTHER PERSON. SUBLESSEE
FURTHER ACKNOWLEDGES AND AGREES THAT TO THE EXTENT PERMITTED BY LAW, THE LEASE
OF THE PROPERTY AND ANY SALE OF THE PROPERTY AS PROVIDED FOR HEREIN IS MADE ON
AN "AS-IS" CONDITION AND BASIS WITH ALL FAULTS.

         (E) If any event described in Section 5.1(a) of the Lease shall occur
in respect of Sublessee, Sublessee's property or the Subleased Premises, or if
Sublessee shall default in the Payment of Rent or Additional Rent hereunder or
in the performance or observance of any of the terms, covenants and conditions
of this Sublease or of the Lease on the part of Sublessee to be performed or
observed, and if such default has not been cured within the applicable grace or
cure period, Sublessor shall be entitled to the lights and remedies herein
provided or reserved by Lessor in the Lease.

         5. ANNUAL RENT. Sublessee shall pay to Sublessor annual rent ("Rent")
in equal monthly installments set forth on Exhibit C attached hereto and
incorporated herein by this reference. Rent shall be due commencing on February
1, 1998 and shall continue to be due on or before the first day of each calendar
month during the term of this Lease without notice, or except as may be
specifically permitted herein or in the Lease, offset or demand.

         6. LATE PAYMENTS. From and after 10 days after Sublessee's receipt of
the due notice of any payment of Rent or Additional Rent, or any other payments
hereunder, interest shall accrued thereon, until paid in full, at the rate of
12% per annum.

         7. SUBLESSEE S IMPROVEMENTS. Alterations, decorations, installations,
additions or improvements in or to the Subleased Premises shall be made at
Sublessee's sole cost and expense and shall be subject to all of the terms and
conditions of the Lease, including, without limitation, the provisions of
Section 3.4 of the Lease.



                                       4
<PAGE>   6


         8. RENTAL ADJUSTMENT. Sublessee shall, for each calendar year during
the term of this Sublease pay to Sublessor as Additional Rent, the full amount
of any real property taxes associated with the Subleased Premises within thirty
(30) days after receiving a bill for any such Additional Rent from Sublessor.
Sublessee shall be responsible for and shall pay in a timely manner all charges
for consumption of utility charges furnished to the Subleased Premises during
the term of this Sublease.

         9. SECURITY DEPOSIT. Sublessee shall deposit with Sublessor upon the
execution of this agreement the sum of $0.00 as a security for the faithful
performance and observance by Sublessee of the terms, provisions and conditions
of this Sublease, including, but not limited to, the payment of rent and
additional rent. Sublessor may use, apply or retain the whole or any part of the
security so deposited to the extent required for the payment of any rent and
additional rent or any other sum as to which Sublessee is in default or for any
sum which Sublessor may expend or may be required to expend by reason of
Sublessee's default in respect of any of the terms, covenants and conditions of
the Sublease, including, but not limited to, any damages or deficiency in the
reletting of the Subleased Premises, whether such damages or deficiency shall
have accrued before or after summary proceedings or other re-entry by Sublessor
or Lessor. If Sublessee shall fully and faithfully comply with all of the terms,
provisions, covenants and conditions of this Sublease, the security shall be
returned to Sublessee after the date fixed as the end of this Sublease and after
delivery of the entire possession of the Subleased Premises to the Sublessor.
Sublessee further covenants that it will not assign or encumber or attempt to
assign or encumber the monies deposited herein as security and that neither
Sublessor nor Sublessor's legal representatives, successors or assigns shall be
bound by any such assignment, encumbrance, attempted assignment or attempted
encumbrance.

         10. EMINENT DOMAIN AND CASUALTY. (A) If the whole or any part of the
Subleased Premises shall be taken or condemned in any manner by any competent
authority or for any public or quasi public use, or damaged or destroyed by
casualty, then, in addition to all other rights of Sublessee under this
Sublease, Sublessee shall have the option to terminate the Sublease by giving
written notice to the other party within thirty (30) days after such casualty or
condemnation, in which event, the term of this Sublease shall cease and
terminate as of the date of such termination and Sublessee shall assign all
insurance proceeds to Sublessor. If Sublessee does not terminate this Agreement,
Sublessee agrees to rebuild the Subleased Premises to its condition prior to the
casualty in accordance with the Lease.

         (B) Sublessee agrees to carry those policies of insurance required
under the Lease with respect to the Subleased Premises, which policy or policies
shall name Lessor and Sublessor as an additional insured or loss payee, as
applicable, which policy or policies shall be issued by a company which is
reasonably acceptable to Lessor and Sublessor and licensed to do business in the
State of Georgia and such policy or policies shall provide that said insurance
shall not and may not be canceled unless thirty (30) days prior written notice
shall have been given to Lessor and Sublessor. Said policy or policies, or
certificates thereof, shall be delivered to Lessor and


                                       5
<PAGE>   7

Sublessor by Sublessee upon commencement of the term of this Sublease and upon
each renewal of said insurance.

         11. NO ASSIGNMENT OR SUBLETTING. Sublessee, for itself, its successors
and assigns, expressly covenants that it shall not assign, mortgage or encumber
this Sublease, nor sublet, nor suffer or permit the Subleased Premises or any
part thereof to be used by others, without the prior written consent of
Sublessor and, if necessary, Lessor in each instance.

         12. QUIET ENJOYMENT. Sublessor covenants and agrees with Sublessee that
upon Sublessee's paying the rent and additional rent and observing and
performing all of the terms, covenants and conditions on Sublessee's part to be
observed and performed, Sublessee may peaceably and quietly enjoy the Subleased
Premises, subject, nevertheless, to the terms and conditions of this Sublease
and to the Lease.

         13. "SUBLESSOR". The term "Sublessor" as used in this Sublease means
only the Tenant under the Lease at the time in question, so that if the Lease
shall be assigned and assumed, such assignor shall be thereupon released and
discharged from all covenants, conditions and agreements of Sublessor thereafter
accruing hereunder after the date of such assignment and assumption, but such
covenants and agreements shall be binding upon each successor assignee.

         14. INDEMNITY . Each party hereto does hereby indemnify the other, and
agrees to hold the other harmless, of and from any claim, damage, liability cost
or expense including reasonable attorneys' fees, which either may suffer or
incur by reason of the failure of the other to perform, observe and comply with
any of the terms, covenants and conditions of this Sublease or the Lease, as
they may affect the Subleased Premises. Sublessee further indemnities Sublessor
to the same extent Sublessor is obligated to indemnify Lessor under the Lease.

         15. BROKERAGE. Sublessor and Sublessee hereby covenant and agree to one
another that no brokerage fees or commissions are due with respect to or in
conjunction with this Sublease, except for Lincoln Property Company Commercial
Service Enterprises, Inc., which has represented Sublessor and which is to be
paid a real estate commission pursuant to a separate agreement with Sublessor,
and Brannon/Goddard Company, which has represented Sublessee and will be paid a
real estate commission by Sublessor. Subject to the foregoing, Sublessor and
Sublessee hereby indemnify one another, and hold one another harmless, from and
against all loss, cost, damage or expense, including, but not limited to,
attorneys' fees and court costs incurred by a party hereto as a result of any
claims for brokerage fees or commissions due which are made by, through or under
the other party thereto.

         16. CONSENT OF LESSOR UNDER LEASE. Sublease is executed subject to such
right as the Lessor under the Lease may have to withhold consent in the manner
and to the extent described the Lease. Promptly upon execution hereof, Sublessor
will submit this Sublease to Lessor for consent (and will also request consent
for the alterations and improvements described in E bit C and will use all
reasonable efforts to obtain such consent as soon as reasonably possible. The
Sublessor shall also submit to Lessor and Lessor's lender such estoppel
certificates


                                       6
<PAGE>   8


and nondisturbance agreements as may be reasonably requested by Sublessee from
time to time and Sublessor will use all reasonable efforts to cause Lessor and
its lender to execute and deliver the same to Sublessee.

         17. NOTICES. Any and all notices which are or may be required to be
given pursuant to the terms of this Sublease or the Lease shall be sent by
registered or certified mail, return receipt requested, or by a nationally
recognized overnight mail carrier, to the parties hereto at their respective
addresses set forth below or to such other addresses as either party shall give
notice of in like manner:

If to Sublessor:
NationsBank, N.A.
401 N. Tryon Street
NCl-021-06-10
Charlotte, North Carolina 28255

with a copy to:
NationsBank, N.A.
715 Peachtree Street
Tenth Floor
GA2-002-10-02
Atlanta, Georgia 30308

If to Sublessee:
5100 LaVista Road
Tucker, Georgia 30085-0049
Attention: J. Randall Carroll, President

         18. CONSENTS. Whenever Sublessor's consent is reasonably conditioned on
obtaining the permission, approval or consent of the Lessor under the Lease,
Sublessor agrees it shall utilize commercially reasonable efforts to obtain such
consent.

         19. FURTHER ASSURANCES. Each of the parties hereto agrees to promptly
take such actions and execute and deliver such estoppel certificates and other
documents as may be reasonably requested by the other party to give effect to
the provisions of this Sublease, including, without limitation, the Purchase
Option defined in "Exhibit D" attached hereto, or to more effectively provide
the benefits intended by this Sublease. Further, in connection with any purchase
of the Subleased Premises by Sublessee as set forth in the Purchase Option,
provided that the terms and conditions of the Purchase Option have been met,
Sublessor agrees to execute any documents reasonably requested by Sublessee in
order to convey fee simple title to the Subleased Premises to Sublessee,
including, without limitation, a quitclaim deed conveying any reversionary
interest which may be held by Sublessor. This paragraph shall survive any
assignment or transfer of the Subleased Premises or this Sublease.


                                        7

<PAGE>   9



         20. MEMORANDUM OF LEASE. Upon the request of Sublessee, Sublessor
agrees to execute a short-form memorandum of this Sublease, in recordable form,
containing certain provisions of this Sublease as may be requested by Sublessee.
Sublessee shall pay any recording costs associated with recording such
memorandum.

         21. BINDING EFFECT. The covenants, conditions and agreements contained
herein shall be binding upon and inure to the benefit of Sublessor and Sublessee
and their respective heirs, devisees, executors, administrators, successors and
ass, as permitted hereby.

         22. GOVERNING LAW. This Sublease is entered into in the State of
Georgia, and its validity and interpretation shall be construed in accordance
with the laws of that State.

         23. EXHIBITS. The following exhibits are attached to this Sublease and
are incorporated into and made a part Of this Sublease:

         (A) EXHIBIT A, the Subleased Premises;
         (B) EXHIBIT B, the Lease;
         (C) EXHIBIT C, the Rent; and
         (D) EXHIBIT D, the Purchase Option.

         IN WITNESS WHEREOF, Sublessor and Sublessee have caused this Sublease
to be executed by their duly authorized partners or officers.

                               SUBLESSOR:
                               NATIONSBANK, N.A.


                               By:   /s/ George M. Snow
                                  ------------------------------------------
                                        George M. Snow
                                        Vice President


                               SUBLESSEE:
                               MOUNTAIN NATIONAL BANK


                               By:   /s/ J. Randall Carroll
                                  ------------------------------------------
                               Name: J. Randall Carroll
                               Title:   Chairman, President and CEO

                                                 [CORPORATE SEAL]



                                        8

<PAGE>   10



                                   EXHIBIT A
                              (SUBLEASED PREMISES)






                                        9

<PAGE>   11



                                    EXHIBIT B
                                     (LEASE)













                                       10

<PAGE>   12



                                    EXHIBIT C
                                     (RENT)

Annual Rent for the Subleased Premises shall be $16.00 per rentable square foot.












                                       11

<PAGE>   13


obligated to provide Sublessee with a title commitment or policy or a survey of
the Subleased Premises. Sublessee shall accept title to the Subleased Premises
in their "AS-IS" condition as set forth in the Sublease.







                                       12