Yesterday, in the presentation about the new Garageband for iPad 2, Apple demoed an interesting feature: The detection of the tap pressure by using the accelerometer. (See t
viggio24 is right. finger-area sensing works fine. (i have some posts here with the trivial line of code to get it). the only problem is that it's not clear what the consequences are if you ship with it enabled; we assume that it simply won't be approved in the best case.