I'm sure this idea has been pondered and maybe somewhere in development for some mobile device...

I don't know the precise implementation, but the idea is basically to meld a mini XBOX Kinect into the place of the front facing camera of a phone like the PRE 3. At first, it wouldn't require two cameras and the laser range finder. Maybe just use the PRE3's front facing camera. The mode could be triggered by being put on the touchstone (so it has certain power source).

The phone could interpret air swipes for slides or gestures like opening or closing a fist for zoom and contract...Pivoting your hand for rotation.

I'm sure this could be worked into some forms of games, menu navigation, media control. It could disable during periods when the screen is being touched, and re-enable when you leave the screen.

I think of this a lot when my phone is mounted to my car dash on its touchstone (needs voice dialing and voice to txt feature). I think if utilized and integrated into WebOS X.0, it would probably draw a lot of wow factor to the OS and devices.

-I'll go submit this to palm's feedback as an idea for a new feature.