Multitouch test: what a very, very cool idea. The main problem right now is that the guessed location of my second finger (ext) is still pretty inaccurate, especially on angles. It looks like the problem is that the touchscreen doesn't report the "false finger" exactly in the middle of the two real fingers.

I bet this is going to require you to write a calibration program; you're going to have to write a data collector that records the location of the first finger (thumb) and second finger (finger), and then you'll lift the first finger (thumb) so the screen can "find" the second finger. When I let go of the first finger (thumb), the second finger marker (finger) slides over under my real finger, so you can use this placement as the calibration...

Just babbling, because this is such a neat idea, and I want it so badly...