Microsoft's Surface table with Portal and Flight Simulator. The DREAM (Dynamically Resizing Ergonomic and Multi-touch) controller is activated by putting five fingers on the table. The joystick will then resize itself to the user.
The controls don't look nearly as efficient as a keyboard and mouse, or as comfortable as a gamepad, but it gives a good idea of the interface we may eventually use on the "iPad XL." Check out the video after the break for the full effect (and be prepared to mute the audio).