Given that, there are many questions about the screen, and to help in that, MacRumors has created a simulation of how such a screen might work.
Multiple leaks point to the new 4-inch screen having an aspect ratio of 16:9 with a resolution of 1,136 x 640. An earlier report showed that the iOS 6 beta SDK supports an extra row of app icons at that resolution.
The video (embedded) shows how the new 4-inch home screen would look. It's been suggested that iOS 6 will letterbox un-optimized apps in portrait mode, and pillar-box them in landscape mode. It's unclear if this will actually take place, but it's similar in concept to the iPad's 2x mode, though not quite so horrific.
This is, of course, a simulation and thus speculative, but a lot of it makes sense. The reality is that we won't know for sure until at least Sept. 12, the rumored date of the launch event, if not longer.