My wild guess on iPhone 5. comments in () indicate my wildest speculation, with some of the technologies not even out yet.

Name will be iPhone 4Gs
Same design as iP4, maybe thinner.(unibody?)
comes in Black, White(or juz a big colour eINK thing wrapping it, so you can have any colour you want =D)
retina display(super amoled), edge to edge screen(4 inch screen?)
A5 chip(1GB RAM, or A6 chip)
Same camera(5mbp front and back, i couldnt bother with higher mbp cam)
4G network compatible. YES 4G wet dream
iOS 5.0

And to make it more human like, leave the antenna problem as it is. Life is more exciting when you recognize and accept another's flaws =P