It looks like Apple might be planning something new. The company has been caught filing a publicly available patent for a "Dual Sided Flip" form factor.
The patent describes a two-piece touchscreen interface that provides contextually distinct interfaces depending on the which program is currently running. When the flip closes, yet another touchscreen appears, providing a total of 3 capacitive input screens. This looks very cool. As with all things Apple and"early patent" related, this could amount to nothing more than the dashed dreams of an idealistic designer. That said, if something like this did manage to make its way to market it could be huge.