...

I don't know anything about a "sunkbd" patch, but I use the following
.Xmodmap file (run from .xinitrc via "xmodmap $HOME/.Xmodmap", of course) for
my Type-5 UNIX keyboard:  (It's a bit "brute force", however.)

------------------------------------------------------------------------------
!
! Sun Type-5 UNIX keyboard remappings 
!
! This remaps the arrow keys properly
!
! By default, the arrow keys on the keypad (Shift-8 = Up, Shift-4 = Left,
! Shift-6 = Right, and Shift-2 = Down) work, but the arrow keys are not
! assigned to any keysym
!
keycode 27 = Up
keycode 31 = Left
keycode 34 = Down
keycode 35 = Right

!
! Now we want the Back Space key to emit the "Delete" keysym
!
keycode 50 = Delete

!
! Other random mappings that aren't on by default
!
! SysRq/Print Screen key
keycode 29 = SunSys_Req Print
! Break/Pause key
keycode 28 = Break Pause
! Alt Graph key
keycode 20 = Mode_switch
! PageUp key
keycode 103 = Prior
! PageDown key
keycode 130 = Next
! Insert key
keycode 51 = Insert
!
! Home, End keys = ???
!
! Open Look Functions
!
! Stop key (SunStop keysym == Cancel)
keycode 8 = SunStop
! Again key (SunAgain == Redo)
keycode 10 = SunAgain
! Props key 
keycode 32 = SunProps
! Undo key (SunUndo == Undo)
keycode 33 = SunUndo
! Front key
keycode 56 = SunFront
! Copy key
keycode 58 = SunCopy
! Open key
keycode 79 = SunOpen
! Paste key
keycode 80 = SunPaste
! Find key (SunFind == Find)
keycode 102 = SunFind
! Cut key
keycode 104 = SunCut
