There is actually a project going on at my university that basically does that. It's an iPhone app that takes the accelerometer and sound input into considerati

There is actually a project going on at my university that basically does that. It's an iPhone app that takes the accelerometer and sound input into consideration. They guys doing that app are graphing the data and have an algorithm rating the "performance". It's supposed to be a little criticism about the current state of privacy (and it includes abilities to share your scores in Twitter and Facebook :) )