By popular request ;-) I've put the image manipulation code on CodePlex (change set 8391). It'd need some more refactoring, but I think as a sample it's good enough.
It requires some practice by the user, especially scaling with two fingers (as you can see in the video).
The movement isn't very smooth. That's because the center of the palm jumps around a bit. It is a trade-off vs. performance. I'll try to improve this.
Edit: I've tried it with the SDK, but the depth limitation is making it almost impossible to work with this sample. I hope Microsoft will add an option so values closer than 850mm can be used soon. And I've found a little problem, the standard depth threshold was used in changeset 8391, so it would not work at all; I've fixed that in 8402.