God it's freaking hilarious how many times I have to remind you people that Steve Jobs was sick when the 3GS was being developed. NOTHING changed design-wise that year except the iPod shuffle, which was clearly just a test to see how well the others could handle it because the next year Steve changed it back. Remember that? Now can everyone please stop suggesting "4S" or "4GS"?
It's not going to happen.
And yeah I just read that Engadget article and they seem to have some good sources for what they are saying, so I trust them in this case.
EDIT:
Oh, and, the iPhone 5 will come out on VZW and AT&T at the same time. In 2009, Rogers lost exclusivity in winter to Bell and Telus, but in June Bell and Telus still got the iPhone 4 at the same time as Rogers. They also allowed their 3GS customers to upgrade to it at the new contract price. No telling if VZW will do that as well, but it seems like the only right thing to do.