I like the way you think, definitely.
But I'm not sure about this concept.
Personally I would not use it since I don't like in-ear headphones, especially those silicone earplug types. I don't mind having my headphones look a little chunky. Some years ago it wasn't really common to go out with big headphones on but now you see teenagers everywhere wearing those Beats and Skullcandy headphones.
It might only work for girls, if they're also able to use it as a headband.
I would also consider an extra degree of freedom in the earbuds, so you can position their angle individually (maybe a ball-bearing or some type of adjustable hose?). They seem to rigidly constrained now and may not fit well in some people's ears.