For someone with any sort of modeling/artistic ability in a program like Maya or 3DS Max, this would be an easy feat to accomplish. As much as the photos really do look like the kind of rendered images Apple throws up on their sites for many of their products, I, too, claim these just being someone's wish.
Having said that, I DO think that colors are a great idea for an iPhone. To the poster who said that people only need black and white; that's ridiculous. Giving people choice and variety is a smart move...why do you think so many of the non-protective skin sites are doing so well? People want difference and variety. I'd absolutely love a Red (same Red as the (RED) iPod) iPhone, and would happily pay a premium for it. Just like the white iPhone, people will pay more money for something to stand out from the crowd.