Are you kidding me? There is no way Apple would have a premium phone in their line up for that much money. Apple has come too far in lowering prices to do this. I'd subscribe to the theory, if there is in fact an iPhone 5, that the iPhone 4s will replace the 4 going forward with the iPhone 5 being the flagship. That is, of course, if there is a 5.
The problem with the iPhone 5 is in mass manufacturing, hence the change in launch schedule. There is physically no way right now that Apple could manufacture 30 million iPhone 5's in one quarter. They're on track to announce that they have sold almost 25 million in the last quarter. They're going to need to sell well over 30 million in this quarter to keep their momentum. That is simply not possible with the iPhone 5. It IS possible with the iPhone 4 + iPhone 4S, and iPhone 5.
The price premium for the iPhone 5 has two causes: Higher ASPs (and profit), and to keep the masses of people on the iPhone 4S until manufacturing can ramp up for the iPhone 5.
Remember, on a 2-year contract, the difference between a $199 phone and a $399 phone is minimal. If a monthly bill is $100, over two years, an iPhone 4S would cost $2600. An iPhone 5 would cost $2800.