HID Compliant TouchScreen for OS X 10.6
Solution 1:
Google found a couple of possibilities; I haven't tried them myself:
- NextWindow - Touchscreen 2700
- Planar Touch - Touchscreen LCD Monitor - PT1710mx 17" Monitor
There's the Wacom Cintiq; while I believe they need drivers I'm sure they'd be available close to day & date.
And an entirely different approach to take might be the Axiotron Modbook.