IIRC, it should be the same board that's in the 8100 or the same form factor as the Q650 or Radius 81/1x0 if you have any of those.
If you don't, I've got a 7100 to hold up against the side of a 128k/Plus.
Have you sourced or identified an LCD or are you still trying to wedge the board in beside your 9" VGA GrayScale?