Straight via Australian filling, a US Patent filling for what looks like an iPhone Nano via Apple emerged recently on the USPTO directory.
The patent shows the iPhone Nano as a small device with screens on both sides. One side is shown as just a touch screen display similar to the iPhone today with menus for all the basic features including phone, text messaging, iPod, camera mode, etc etc etc.
The flip side however is where things get different. The patent shows it is a "force-sensitive touch-surface." This surface would control a click wheel like everyone is used to one the iPod of today. Somehow you control the screen side of the iPhone Nano via the controls on the back blind. Maybe the force-sensitive touch-surface has some etchings back there so you can feel your way around -- or something. There are also images of keys and whatnot being on the surface, specifically something that resembles a dialer pad.