Me too.
That's why I made this quick mockup of what the physical outer dimensions of an iPhone would have to be, in order to fit a 5" screen.
If they made the iPhone into a completely square brick (even more so than now), and kept the bezel to 1 mm or so, existing iPhone height is enough and the width would have to increase from 2.31 inch to 2.5 inch. Not too bad IMO.
Of course, they'd also have to figure out where to put the front facing elements (ear piece, FaceTime camera, home button), perhaps on the sides of the phone or behind the screen somehow.
I personally like the home button where it's at on the iPhone (one of the things I miss on the Android).
Anyway, basically all the stuff you're trying not to include (like the FT camera and the light sensor you neglected to mention) would have to be there, so you'll need to change your dimensions somewhat.