The iphone 5 for sure will bring in and usher the next iphone on all simultaneous networks that will be the releasing the iphone 5 and this means there will be a rush for iphone 5 accessories which will include iphone 5 cases and covers.
The iphone 5 basically will be the biggest iphone that will be on the market and im sure that people will love having something that they can take back and forth on both networks.
Probably another thing that we will love too will be the ability to move back and forth between networks so you dont have to worry about selling your phone everytime you decide to move networks.
If you are looking for a community for your iphone 5 then go and check out the iphone 5 forum