Some iPhone Devs get Suped Up Models with A5 Chip
venturebeat.com
venturebeat.com
I don't see how it means that, surely even if advance prototypes were available then given the debacle last time they'll be kept even more under-wraps this time. Putting the new cpu into an "old" phone seems the perfect compromise for Apple - no matter what stage of dev the iPhone 5 is at.
The weird situation of the iPhone having double the RAM of its iPad counterpart could be repeated.
Perhaps there is something they know that makes this differentiation worthwhile. But maybe the specs will be the same after all. Who knows yet?
Now if that's because of iOS then I guess I understand what you are feeling... (but I don't see Apple not letting you update iPhone 4 to iOS 5).