Regarding multitouch, the iPhone seems to be their new baby, and has demonstrated that Apple is open to taking a device that historicly has had a physical keyboard and replacing it with a touchpad and slick software. I doubt we will see a wedge iMac, but I can envision a G4 redux, so that the screen swings down to a drafting table angle and position. It may be a long way off, so I would expect a tablet first, somewhere between the iPhone and Macbook.
The mouse never took away the keyboard and the multi-touch screen will not take away the mouse or the keyboard.
Your current design won't work for 2 reasons:
1. There is no room for the keyboard in front of the multi-touch screen when it is in the multi-touch position.
2. You would have to lock the screen in place to put it in the multi-touch position and that wouldn't work because it could break easily and it would be annoying to lock in in position and unlock it from the multi-touch position time and time again. Apple wouldn't make users deal with this problem.
If you can fix those 2 problems then it might work but I personally don't like that style as much as the wedge that I made.
Edit: My second reason was already stated (credit to dcv):
That's much more feasible and user-friendly... something with a tiltable display and small footprint. It'd have to be a pretty "tight" hinge (or somehow lockable in certain positions) though to avoid the display moving around too much when touching it.