Here's one we've heard before, and we're not talking about Troll Touch. This time around, DigiTimes is reporting that Sintek Photonics is shipping touch panels to Apple for testing in iMacs. The panels are supposedly about 20" in size, and the same projected capacitance type currently used on the iPad, iPhone, and iPod touch.
As Engadget notes, the image shown here was extracted from an unrelated Apple patent, and it doesn't necessarily have anything to do with this rumor, other than providing an idea of how it could be used. Of course, Apple and most large companies patent all sorts of things that are never produced.
Would you want to hover your arm above that thing all day long? I'm not sure I would.