I think it's an interesting idea, and I like the concept but the mobile / cell phone market is so different to Apple's other business products. I'm the kind of person who would buy a new iPod just because I like the colour, and then give my old one to a friend. I can't do that with my iPhone because each handset comes tied to its own contract. Increasing the choice of iPhones just seems like it will annoy the early adopters who then can't get the latest model until they 'upgrade' to the next one.
That's my ho anyway.