According to recent patent filings it looks like Apple is looking past its current candy bar iPhone design to a future that may include an iPhone flip design. UnwiredView seems to suggest that this new design could even be the iPhone nano. That is pure speculation at this point but it sure would be nice to have a smaller version of the iPhone.

"The main idea with this device is to separate capacitive touch sensor array and the phone display into two separate units. Then put the touch sensor array on a translucent (transparent) panel, make this panel touch sensitive on both sides - top and bottom and connect them with a hinge."

Check out the source link below for the particulars.