neatojones,

this is primarily hardware related.
what they manage is simply not possible with standard 4 or 5 wire touchscreen.

the touch screen they are using is essentially a camera with many pixel points, the 4 wire resistive just get a value from each edge of the touch screen.

whatever code you are thinking is their translation stuff buried inside the controller chip before it even reaches the host operating system.

If you could give me a similar LCD overlay and usb connection which gave back a bitmap of data the libraries to identify fingers already exist (tabletop multitouch with webcams and projectors and paper will use them).