I've been thinking a lot about this, and this is what made think that Apple really has BIG plans for this: When Steve Jobs introduced the iPhone, he compared multitouch to the mouse and the click-wheel:
"We have been very lucky to have brought a few revolutionary user interfaces to the market - the mouse, the click wheel, and now Multi-Touch."
So Steve compares multitouch with the mouse. Would he if it were only to be used in a phone. No, he wouldn't.
Have a look at my post:
http://brilliantdays.com/multitouch-will-revolutionize-your-computer/
It also links to another post about multitouch (both with videos). You can see how much multitouch has developed in just a short time.
There's also some background on multitouch and which technology Apple uses in the iPhone and (hopefully) future Apple displays with multitouch.
Multi-Touch Coming to a Mac Near You?