I really like the idea but I do see one problem with the premise. I've been programmed to jolt awake from the sound of my alarm. I've been listening to the same alarm for years and my body just knows it has to GET UP NOW when that noise is made. Hell even if I hear it halfway through the day it's like I feel a static shock.
Perhaps it could play a base line noise that's guaranteed to wake you up and fade into the music?