Welcome to MacMod first of all. In order to use another touchscreen there is quite a bit to consider. Drivers, pin out configuration for the wiring and mount points.

Honestly, your best bet is going to be to try and put a trolltouch component over it or maybe even taking the touch component from the waccom. There was another tread on this recently. And there are multiple threads on the trolltouch.
"Fix it 'til it Breaks."

Jacob - EiC & Director of Technology
Mac Pro Quad 2.66 - 4GB RAM
160 GB SATA RAID 1 - 650 GB Storage
Quad 19" Widescreen LCDs
Accessorized to the Hilt