I just don't see a >5" iPhone coming.
That is just so not Apple.
At least, it would be so contradictory on one thing, how would they explain the deep-minded one hand usage.
Would you really prefer that

Also people have various hand sizes and visual acuity. People will be able to choose the right phone for them.
Apple in the past has made iPods in many form factors. They should have done this for iPhones much sooner.
I wonder why they haven't been any iPod touch leaks in new sizes.
Unless... They will use the new form factor for the iPod Touch and the iPhone...