It'd be nice if iOS allowed the installation of additional keyboards easily. The last I recall apps could define their own but that doesn't extend outside of its sandbox. I would expect that with a taller iPhone screen coming, we may see some keyboard changes in iOS 6. A version with numbers on top would make a lot of sense - PITA having to flip between letters and numbers. But then it's a PITA flipping to reach for a comma or question mark too.