Hmm . . . I know that there are stylus-based interfaces that might do some of what you seem to want. HP has the iPAQ, I think if you Googled stylus, you'd probably get a ton of results, too. The two hands thing is a no go, though. Most touchscreens can only deal with one/two input at a time.

I think that Apple will probably come up with something like this, and has applications in their latest OS that are similar to what you are talking about. They just need a touchscreen Macbook, or touchscreen screen.