huge multitouch sceen

I doubt it. The current limits on the accenture thing are two users. Jeff Han's system can handle many touches.

There are bunches of ways to do touch screen type systems. I recently gave a talk at the Maker's Faire on the subject. Here's the webpage I created to go along with it. It's rough, but informative:

http://www.mortalspaces.com/diytouchpanels/

sasha.