<PAGE>

                                                                   EXHIBIT 10.51

THE SECURITIES REPRESENTED BY THIS WARRANT AND THE COMMON STOCK ISSUABLE THEREBY
HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE
"SECURITIES ACT"), OR ANY OTHER APPLICABLE SECURITIES LAW. THE SECURITIES
REPRESENTED BY THIS WARRANT MAY NOT BE TRANSFERRED, EXCEPT PURSUANT TO AN
EFFECTIVE REGISTRATION STATEMENT UNDER, OR IN A TRANSACTION EXEMPT FROM
REGISTRATION UNDER, THE SECURITIES ACT AND IN ACCORDANCE WITH ANY OTHER
APPLICABLE SECURITIES LAWS.


                            STOCK PURCHASE WARRANT 
                            EQUALNET HOLDING CORP.

     This Stock Purchase Warrant (this "Warrant"), issued this 15th day of
April, 1998, by EqualNet Holding Corp., a Texas corporation (the "Company"), to
Mezzanine Telecom, Inc., formerly known as Creative Communications
International, Inc. (the "Holder").


                                  WITNESSETH:

                                   ARTICLE I

                   ISSUANCE OF WARRANT; TERM; EXERCISE PRICE

     For and in consideration of the promises and the mutual covenants in this
Warrant and other good and valuable consideration, the receipt and sufficiency
of which are hereby acknowledged, the Company hereby grants to the Holder,
subject to the provisions hereinafter set forth, the right to purchase 85,000
shares of Common Stock, $.01 par value per share, of the Company (the "Common
Stock"). The Warrant shall be exercisable at any time after the date hereof and
on or before 5:00 p.m. Houston, Texas time on November 1, 2001 (the "Expiration
Date "). The exercise price per share for which all or any of the Warrant Shares
(as hereinafter defined) may be purchased pursuant to the terms of this Warrant
shall be $7.50.

                                   ARTICLE 2

                                  DEFINITIONS

     As used herein, the following terms shall have the meanings set forth
below:

     1.  "Company" shall mean EqualNet Holding Corp., a Texas corporation, and
shall also include any successor thereto with respect to the obligations
hereunder, by merger, consolidation or otherwise.
<PAGE>
 
     2.  "Common Stock" shall mean and include the Company's Common Stock, par
value $.01 per share, authorized on the date of the original issue of this
Warrant and shall also include (i) in case of any reorganization,
reclassification, consolidation, merger, share exchange or sale, transfer or
other disposition of assets, the stock or other securities provided for herein,
and (ii) any other shares of common stock of the Company into which such shares
of Common Stock may be converted.

     3.  "Exercise Price" shall mean the initial purchase price of $7.50 per
share of Common Stock payable upon exercise of the Warrant, as adjusted from
time to time pursuant to the provisions hereof

     4.  "Market Price" for any day, when used with reference to Common Stock,
shall mean the price of said Common Stock determined by reference to the last
reported sale price for the Common Stock on such day on the principal securities
exchange on which the Common Stock is listed or admitted to trading or if no
such sale takes place on such date, the average of the closing bid and asked
prices thereof as officially reported, or, if not so listed or admitted to
trading on any securities exchange, the last sale price for the Common Stock on
the National Association of Securities Dealers national market system on such
date, or, if there shall have been no trading on such date or if the Common
Stock shall not be listed on such system, the average of the closing bid and
asked prices in the over-the-counter market as furnished by any NASD member firm
selected from time to time by the Company for such purpose.

     5.  "Outstanding" when used with reference to Common Stock, shall mean
(except as otherwise expressly provided herein) at any date as of which the
number of shares thereof is to be determined, all issued shares of Common Stock,
except shares then owned or held by or for the account of the Company.

     6.  "Person" shall mean an individual, corporation, limited liability
company, partnership, limited partnership, joint venture, joint stock company,
firm, company, syndicate, trust, estate, association, governmental authority,
business, organization or any other incorporated or unincorporated entity.

     7.  "Trading Days" shall mean any days during the course of which the
principal securities exchange on which the Common Stock is listed or admitted to
trading is open for the exchange of securities.

     8.  "Warrant Shares" shall mean the shares of Common Stock purchased or
purchasable by the holder hereof upon the exercise of the Warrant.

                                      -2-
<PAGE>
 
                                   ARTICLE 3

                              EXERCISE OF WARRANT

     1. Method of Exercise. The Warrant represented hereby maybe exercised by
the holder hereof, in whole or in part, at any time and from time to time on or
after the date hereof until 5:00 p.m., Houston, Texas time, on the Expiration
Date. To exercise the Warrant, the holder hereof shall deliver to the Company,
at the Warrant Office (as hereinafter defined) designated herein, (i) a written
notice in the form of the Subscription Notice attached as an exhibit hereto,
stating therein the election of such holder to exercise the Warrant in the
manner provided in the Subscription Notice; (ii) payment in full of the Exercise
Price (A) in cash or by bank check for all Warrant Shares purchased hereunder,
or (B) through a "cashless" or "net-issue" exercise of each such Warrant
("Cashless Exercise"); the holder shall exchange each Warrant subject to a
Cashless Exercise for that number of Warrant Shares determined by multiplying
the number of Warrant Shares issuable hereunder by a fraction, the numerator of
which shall be the difference between (x) the Market Price and (y) the Exercise
Price for each such Warrant, and the denominator of which shall be the Market
Price; the Subscription Notice shall set forth the calculation upon which the
Cashless Exercise is based, or (C) a combination of (A) and (B) above; and (iii)
this Warrant. The Warrant shall be deemed to be exercised on the date of receipt
by the Company of the Subscription Notice, accompanied by payment for the
Warrant Shares and surrender of the Warrant, as aforesaid, and such date is
referred to herein as the "Exercise Date". Upon such exercise, the Company
shall, as promptly as practicable and in any event within five business days,
issue and deliver to such holder a certificate or certificates for the full
number of the Warrant Shares purchased by such holder hereunder, and shall,
unless the Warrant has expired, deliver to the holder hereof a new Warrant
representing the number of Warrant Shares, if any, that shall not have been
exercised, in all other respects identical to this Warrant. As permitted by
applicable law, the Person in whose name the certificates for Common Stock are
to be issued shall be deemed to have become a holder of record of such Common
Stock on the Exercise Date and shall be entitled to all of the benefits of such
holder on the Exercise Date, including without limitation the right to receive
dividends and other distributions for which the record date falls on or after
the Exercise Date and to exercise voting rights.

     2.  Expenses and Taxes. The Company shall pay all expenses and taxes
(including, without limitation, all documentary, stamp, transfer or other
transactional taxes) other than income taxes attributable to the preparation,
issuance or delivery of the Warrant and of the shares of Common Stock issuable
upon exercise of the Warrant.

     3.  Reservation of Shares. The Company shall reserve at all times so long
as the Warrant remain outstanding, free from preemptive rights, out of its
authorized but unissued shares of Common Stock, solely for the purpose of
effecting the exercise of the Warrant, a sufficient number of shares of Common
Stock to provide for the exercise of the Warrant.

                                      -3-
<PAGE>
 
     4.  Valid Issuance. All shares of Common Stock that may be issued upon
exercise of the Warrant will, upon issuance by the Company, be duly and validly
issued, fully paid and nonassessable and free from all taxes, liens and charges
with respect to the issuance thereof and, without limiting the generality of the
foregoing, the Company shall take no action or fail to take any action which
will cause a contrary result (including, without limitation, any action that
would cause the Exercise Price to be less than the par value, if any, of the
Common Stock).

     5.  Purchase Agreement. The Warrant represented hereby is a duly authorized
issue and sale of a warrant to purchase Common Stock issued and sold pursuant to
that certain Asset Purchase Agreement between the Company and the Holder, dated
the date hereof (the "Agreement").

     6.  No Fractional Shares. The Company shall not be required to issue
fractional shares of Common Stock on the exercise of this Warrant. If any
fraction of a share of Common Stock would, except for the provisions of this
Section, be issuable on the exercise of this Warrant, the Company shall pay an
amount in cash calculated by it to be equal to the Market Price of one share of
Common Stock at the time of such exercise multiplied by such fraction computed
to the nearest whole cent.

                                   ARTICLE 4

                                   TRANSFER

     1.  Warrant Office. The Company shall maintain an office for certain
purposes specified herein (the "Warrant Office"), which office shall initially
be the Company's offices at EqualNet Plaza, 1250 Wood Branch Park Drive,
Houston, Texas 77079-1212 and may subsequently be such other office of the
Company or of any transfer agent of the Common Stock in the continental United
States as to which written notice has previously been given to the Holder. The
Company shall maintain, at the Warrant Office, a register for the Warrant in
which the Company shall record the name and address of the Person in whose name
this Warrant has been issued, as well as the name and address of each permitted
assignee of the rights of the registered owner hereof.

     2.  Ownership of Warrant. The Company may deem and treat the Person in
whose name the Warrant is registered as the holder and owner hereof until
provided with notice to the contrary.

     3.  Restrictions on Transfer of Warrant. Subject to the provisions of
Section 4.4 hereof this Warrant may be transferred, in whole or in part, by the
Holder. The Company agrees to maintain at the Warrant Office books for the
registration and transfer of the Warrant. The Company, from time to time, shall
register any transfer of the Warrant in such books upon surrender of this
Warrant at the Warrant Office properly endorsed or accompanied by appropriate
instruments of transfer and written instructions for transfer. Upon any such
transfer and upon payment by the Holder or its transferee of any applicable
transfer taxes, a new Warrant shall be issued to the transferee and the
transferor (as their respective interests may appear) and the surrendered
Warrant shall be canceled

                                      -4-
<PAGE>
 
by the Company. The Company shall pay all taxes (other than securities transfer
taxes or income taxes) and all other expenses and charges payable in connection
with the transfer of the Warrant pursuant to this Section.

     4.  Compliance With Securities Laws Regarding Transfers. Neither this
Warrant nor the Warrant Shares have been registered under the Securities Act of
1933, as amended (the "Securities Act"), or any state securities laws ("Blue Sky
Laws"). The Holder hereby agrees and acknowledges that this Warrant and the
Warrant Shares have been acquired for investment purposes and not with a view to
distribution or resale and the Warrant Shares may not be made subject to
security interest, pledged., hypothecated, sold or otherwise transferred without
an effective registration therefor under the Securities Act and such applicable
Blue Sky Laws or an opinion of counsel (which opinion and counsel rendering same
shall be reasonably acceptable to the Company) that registration is not required
under the Securities Act and under any applicable Blue Sky Laws. The certificate
representing the Warrant Shares shall bear substantially the following legend:

          "THE SECURITIES REPRESENTED BY THIS CERTIFICATE (THE "SECURITIES")
     HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE
     "SECURITIES ACT"), OR THE SECURITIES LAWS OF ANY STATE AND ARE BEING
     OFFERED AND SOLD IN RELIANCE ON EXEMPTIONS FROM THE REGISTRATION
     REQUIREMENTS OF THE SECURITIES ACT AND SUCH LAWS. THE SECURITIES HAVE BEEN
     ACQUIRED FOR INVESTMENT AND MAY NOT BE SOLD OR OFFERED FOR SALE IN THE
     ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT FOR THE SECURITIES OR AN
     OPINION OF COUNSEL OR OTHER EVIDENCE ACCEPTABLE TO THE CORPORATION THAT
     SUCH REGISTRATION IS NOT REQUIRED."

Other legends as required by applicable federal and state laws may be placed on
such certificates. The Holder and the Company agree to execute such documents
and instruments as counsel for the Company reasonably deems necessary to effect
compliance of the issuance of this Warrant and any Warrant Shares issuable upon
exercise hereof with applicable federal and state securities laws. The Holder
agrees that the Company may decline to permit a transfer of this Warrant if the
proposed transferee does not meet then applicable qualifications for investors
in securities offerings exempt from registration.

     5.  Stop transfer instructions will be imposed with respect to the Warrant
Shares so as to restrict resale or other transfer thereof.

                                      -5-
<PAGE>
 
                                   ARTICLE 5

                                 ANTI-DILUTION

     1.  In case at any time or from time to time after the date of this
Warrant, the holders of Common Stock shall have received or shall have become
entitled legally to receive:

         (i) other or additional stock or other securities or property (other
     than cash) by way of a dividend or other distribution or

         (ii) other or additional (or less) stock or other securities or
     property (including cash) by way of a stock-split, spin-off, split-up,
     reclassification, combination of shares or similar corporate rearrangement
     (but not including any cash dividends),

then and in such case the Holder, upon the exercise of this Warrant as provided
in Article III hereof, shall be entitled to receive, in lieu of (or in addition
to, as the case may be) the Warrant Shares theretofore receivable upon the
exercise of this Warrant, the amount of stock and other securities and property
(including cash in the case referred to in clause (ii) above) which the Holder
would have held on the date of such exercise if, on the date of such conversion,
dividend, distribution, corporate rearrangement or such other event as described
in clause (ii) above, the Holder had been the holder of record of the number of
Warrant Shares receivable upon exercise of this Warrant and had thereafter,
during the period from the date thereof to and including the date of such
exercise, obtained such Warrant Shares and all other or additional (or less)
stock and other securities and property (including cash in the case referred to
in clause (ii) above) receivable by it as aforesaid during such period.

                                   ARTICLE 6

                                 MISCELLANEOUS

     1.  Entire Agreement. This Warrant, together with the Agreement and the
Registration Rights Agreement, contains the entire agreement between the Company
and the Holder hereof

     2.  Governing Law. This Warrant shall be governed by and construed in
accordance with the laws of the State of Texas.

     3.  Waiver and Amendment. Any term or provision of this Warrant may be
waived at any time by the party which is entitled to the benefits thereof and
any term or provision of this Warrant may be amended or supplemented at any time
by agreement of the holder hereof and the Company, except that any waiver of any
term or condition, or any amendment or supplementation, of this Warrant shall be
in writing. A waiver of any breach or failure to enforce any of the terms or

                                      -6-
<PAGE>
 
conditions of this warrant shall not in any way effect, limit or waive a party's
rights hereunder at any time to enforce strict compliance thereafter with every
term or condition of this Warrant.

     4.  Illegality. In the event that any one or more of the provisions
contained in this Warrant shall be determined to be invalid, illegal or
unenforceable in any respect for any reason, the validity, legality and
enforceability of any such provision in any other respect and the remaining
provisions of this Warrant shall not, at the election of the party for whom the
benefit of the provision exists, be in any way impaired.

     5.  Copy of Warrant. A copy of this Warrant shall be filed among the
records of the Company.

     6.  Notice. Any notice or other document required or permitted to be given
or delivered to the Holder hereof shall be in writing and delivered at, or sent
by certified or registered mail to such holder at the last address shown on the
books of the Company maintained at the Warrant Office for the registration of
this Warrant or at any more recent address of which the holder hereof shall have
notified the Company in writing. Any notice or other document required or
permitted to be given or delivered to the Company, other than such notice or
documents required to be delivered to the Warrant Office, shall be delivered at,
or sent by certified or registered mail to, the offices of the Company at
EqualNet Plaza, Attn: General Counsel, 1250 Wood Branch Park Drive, Houston,
Texas 77079-1212 or such other address within the continental United States of
America as shall have been furnished by the Company to the holder of this
Warrant.

     7.  Limitation of Liability; Not Stockholders. No provision of this Warrant
shall be construed as conferring upon the holder hereof the right to vote,
consent, receive dividends or receive notices (other than as herein expressly
provided) in respect of meetings of stockholders for the election of directors
of the Company or any other matter whatsoever as a stockholder of the Company.
No provision hereof, in the absence of affirmative action by the holder hereof
to purchase shares of Common Stock, and no mere enumeration herein of the rights
or privileges of the holder hereof, shall give rise to any liability of such
holder for the purchase price of any shares of Common Stock or as a stockholder
of the Company, whether such liability is asserted by the Company or by
creditors of the Company.

     8.  Exchange, Loss, Destruction, etc. of Warrant. Upon receipt of evidence
reasonably satisfactory to the Company of the loss, theft, mutilation or
destruction of this Warrant, and in the case of any such loss, theft or
destruction upon delivery of an appropriate affidavit in such form as shall be
reasonably satisfactory to the Company and include reasonable indemnification of
the Company, or in the event of such mutilation upon surrender and cancellation
of this Warrant, the Company will make and deliver a new Warrant of like tenor,
in lieu of such lost, stolen, destroyed or mutilated Warrant. Any Warrant issued
under the provisions of this Section in lieu of any Warrant alleged to be lost,
destroyed or stolen, or in lieu of any mutilated Warrant, shall constitute an
original contractual obligation on the part of the Company. This Warrant shall
be promptly canceled by the Company upon the surrender hereof in connection with
any exchange or replacement. The Company

                                      -7-
<PAGE>
 
shall pay all taxes (other than securities transfer taxes or income taxes) and
all other expenses and charges payable in connection with the preparation,
execution and delivery of the Warrant pursuant to this Section.

     9.  Headings. The Article and Section and other headings herein are for
convenience only and are not a part of this Warrant and shall not affect the
interpretation thereof.

    10.  Registration Rights. The Warrant Shares shall be entitled to such
registration rights under the Securities Act and under applicable state
securities laws as are specified in the Registration Rights Agreement.

    11.  Replacement of Old Warrant. This Warrant, together with that certain
stock purchase warrant of even date herewith numbered W-9 issued to John Dalton
amends and restates in its entirety, and supersedes and replaces in all
respects, that certain stock purchase warrant issued to Creative Communications
International, Inc. on November 12, 1996.



                          [SIGNATURE PAGE TO FOLLOW]


                                      -8-
 
<PAGE>
 
     IN WITNESS WHEREOF, the Company has caused this Warrant to be signed in its
name.

Dated: April 15, 1998


                             EQUALNET HOLDING CORP.

                             By:  /s/ Dean H. Fisher
                                ------------------------------------

                             Name: Dean H. Fisher
                                  ----------------------------------

                             Title: Senior Vice President
                                   ----------------------------------

                                      -9-