I just thought I’d throw this out here, since I cannot try it myself due to higher costs (projectors are damn expensive).
Basically, one could use 2 projectors, with polarizing filters (so one has to use matching glasses), and achieve a 3D effect by rendering a scene with 2 different angles, one on each projector.
This is nothing new or special anymore today, but the projector-using setup in many of our multitouch tables makes this relatively simple.
The down side of course: projectors are quite costly. (I have yet to calculate the exact sum for my setup, but it does look like the projector alone makes up over 50% of it all)