From Florian in Vienna comes the visualization of the argument that Arn from MacRumors and I had last night. Can a 4-inch display fit on the current hardware?

Maybe those 4Bs that Apple is investing in display technology is what gets them to the edges like that.  The current phone is already glass so it would be something in the underlying LCD display that pushes them to the edges.  No phone on the market can do this now btw.