I'm very interested in this. I have several projects for the Arduino for which I need color screens, and having touchscreen controls would be a plus. Cheap Android tablets can be had for as low as $50, versus $80 or more for a 7 inch touchscreen.
At the moment, I have nothing more useful to add. I'm a rank newbie to Arduino programming, most of my programming experience was in solder and to a lesser extent in Basic.