Motorized wheelchair as parts for CNC?

I wrote a long post this morning that apparently Yahoo ate, so
here's a short version:

Just an idea:

I think that with a minimum of work, the two servo drives,
controller, power supply and control mechanisms off of a motorized
wheelchair can be adapted to the X and Y axis of a CCNC machine.
The motors are usually NEMA 42 with gear reducers. While the
joystick connections are a closely guarded secret, they can be
easily reverse engineered (I did it once about 20 years ago). The
controllers also have an industry standard interface (basic on-off
and directional contacts) ending in a DB-9 connector. While the
chairs are expensive new (think what a new Bridgeport is worth), I'm
sure with a little imagination and a few bucks, you may be able to
end up with an almost complet 2 axis servo system.

Anyone ever try this?

Regards,
Jeff