There is no way Apple will put a larger screen on the iPhone 5. It's simply because Apple favours standard and they won't ask developers to redo their apps to fit a larger retina screen after they have just done it for the retina iPhone 4 screen. They won't make it bigger, just accept that fact. They didn't make it smaller on the iPad 2 like many people suggested initially. Apple will stick to it's popular screen size, because a larger one can't be built into a unit the same size without changing the aspect ratio. And apple will surely not do that.
I predict iPhone 5 will have:
- up to 64gb memory
- 512 of ram
- Apple A5 chip
- 8 Mp rear cam (or less)
- Same display as iPhone 4
- Similar design; improved antenna while an aluminium back seems unlikely to me.
- GSM/CDMA support
the rest will be the same like on the iPhone 4. Don't get your hopes to high, people, because you will be disappointed... Apple strategically makes their devices only a little bit better at the time, so they always can speak about the next model with great words. Seriously, they won't make the iPhone 5 a lot better than the 4, so they have more to offer on the iPhone 6. E.g. on the iPad one I think a little space between glass and screen was intentionally left there to be able to make the iPad 2 look so much thinner...
Nothing against Apple, I really like them, but this is the way they work...