> I think a new 16C84 with a built in
>
> 4x4 key matrix scanner (74C922) and a
> led display driver (MAX7219) would
>
> do extremely well in the market.

Any PIC with at least 24 I/O pins should work for this application, though
eight pins may need transistors to "boost" their outputs.  Other than boosting
the sinking abilities of eight I/O pins, what else would you want as features?