This one if for Jeff. A company in Darien, CT (right up the road from me) called HoloTouch is now licensing their technology. From the site:
Combining holographic images of what would otherwise be the buttons of cell phones, PDAs, laptops, video games or hand-helds with a wave sensor scanning the plane of those images, HoloTouch enhances comfortable, reliable operation, where keypad size has shrunk below normal finger size, and continues to dwindle. With HoloTouch, images of keypads can be any size, entirely independent of the size of the hardware. Holographic images of the keypad are projected into the air in front of the equipment. An infra-red detector scans the plane of those holographic images to detect the intrusion of a finger into the desired portion of those images, identifies which number or symbol has been selected, and transmits that selection from the equipment’s internal software, much the same way pressing a button on an ordinary keypad would.