the touch screens that are generally available now are very limited in their input capabilities, and no where near sensitive enough to handle the kind of manipulations that were going on in the demo movie. there are serious pressure sensitivity manipulations going on there that are pretty much impossible with the common screens, not to mention the multiple inputs possible (most screens that i've seen can't handle multi-inputs).
there is -serious- computing going on in the monitor, i'll bet, differentiating the various inputs. most of that is done in the monitor modules in common touch screens now.
btw, check out
www.earthlcd.com - they have a lot of cool touch screens there. gonna get one for the ole' custom pc.