Recently-revealed engineering samples of iPhone 4s have been found to have 64 GB of memory -- see picture above from Unwire, and this M.I.C. Gadget story -- showing that there's no physical reason why the iPhone 5 couldn't have this much memory.
The iPad 2 has already been criticised for sticking with the earlier version's 64 GB limit, and releasing an iPhone 5 with the earlier model's 32 GB limit
