Graphic design for a music instruction app - repost

I'm creating an app to help music students master their instrument. I need a creative person skilled in using software like Illustrator, Photoshop, etc, to design the front end of the app, meaning the graphical interface, or the graphical environment if you prefer. I'm looking for innovative design...the kind of thing that makes people say "Not only does it work, but it's a really beautiful app, too." The ideal bidder will understand how music works and should probably play a musical instrument. The app is first being made for Android, then subsequently for iPad/iPhone and for PC. In the long run this should turn out to be a family of apps, so the work will be ongoing for a while. This project is the first step. Francophones bienvenus à postuler en français aussi.