Hi There- MMF is great, thanks for the hard work!

It would be interesting to incorporate this type of functionality:

"SLAP :  Silicone Illuminated Active Peripherals" – this uses both FTIR and Diffuse IR lighting to acheive finger as well as object recognition:  http://hci.rwth-aachen.de/slap  (see the videos)

This might be a starting point:  http://www.dealextreme.com/det…..x/sku.5358

But if you're using an SMK screen rather than a projector-based multitouch table, the SMK srceen might not recognize the silicon keyboard (it depends on the technology it uses, resistive wouldn't work but capacitive might)…  from their demos, it looks like the SLAP people are just recognizing an object via it's unique geometry of resting points.