If you have ever seen the EZ- series of paper models, I think they fit well with the idea of a modular system. They basically skip over the whole projection idea, but if you were to create just solid white versions of the various shapes and project onto them I think you would have an awesome hybrid environment to play on.

Here's a link to one of the sets: http://rpg.drivethrustuff.com/produc..._id=59439&it=1

If you look near the bottom you'll see the special "tab system" they use to keep the pieces modular and able to stay joined.