Hum....Cell phone cases. A case for a cell phone. Man, I wish I would have thought of that. Hell, I could even make mine out of Titanium or plastic or stainless or ...lol just kidding...
Seriously, you have to get a bunch (maybe a dozen) of good working prototypes, have some friends try them for a while, work out the bugs, have more made, then start marketing them like crazy.
Oh, and if you need some billet Iphone cases, I can get you some.