I know there are rumors about a possible red iPhone coming out this holiday season (which would be awesome in my opinion), but as for the 2nd generation? Apple is still making a killing off the first generation, I don't figure they will release another one until sometime late next year too.
Hero, don't wait. The iPhone is a computer that is being updated all the time. There is no real reason to wait for the "next best version". The current model will be upgraded for another 6 months. Why wait that long for a really cool tool?
And I'm certain different colored shells will be available soon. Only a Apple or ATT technician will be authorized to change it out for you.
And one more thing....I paid $532 (including taxes) for my iPhone and don't give a rat's ass that it is now cheaper by $200. I enjoy the iPhone that much. Don't wait, jump in.