Samsung recently applied for a brand new patent involving a dual touch sensor device (tablet or large smartphone). Said device will support input via touch and gestures both at the front and the back of the unit. This means that the new technology could be incorporated into a Samsung tablet with dual displays.
Zooming gestures could also be supported on both the rear and front surface, making the tablet ideal for new ways of browsing the web or gaming on the go. This technology has been talked about a lot recently, with Motorola’s Backflip smartphone making a step in this direction, by integrating a touchpad on the back of the display.
Also, Notion Ink’s Adam prototype tablet also comes with a rear touchpad and at some point the iPhone 4 was rumored to include one.