Out of curiosity. I know I've seen certain programs that are able to directly tap into the Synaptics driver (Synaptics makes touchpads for practically every laptop under the sun) instead of rely on mouse movements. (For instance, I'm blanking on the name of it but there was a weird project I tooled around with years ago that let you use your laptop touchpad as a Graffiti input - you could draw letters and such.) A quick GOogle search brings up some Java libraries concerning this (but this is built in C++/XNA, iirc.) I think it'd certainly translate well to osu, but that leads to the question: is the demand too small? Or are other people interested in it?