There is no way the resolution is changing. What's all this talk about Resolution Independence? That is a HUGE switch to a Cocoa SDK that is in use for over 20,000 Apps.
Its easy enough to fake, lcd's can pretend there have a lower resolution. Also, 3D is resolution independent, images can be upscaled and pre-made buttons only need an update from Apple. There was a reason Apple wants the developers to use the buttons from the SDK with automatic alignment.
There is no way on earth that Apple would never release a higher resolution iPhone, this has to be anticipated from the start and is most probably already implemented in the core software.