I've always loved 3D printing... I live right down the street from a place - literally - that works in it, and I've been fascinated by some of their PR stuff.
If I had monies for this, I would buy a 3D printer, and I'd use it to really speed up my creative process. Plus, as far as props go, one could just make a model of the prop, print it, mold it, cast it, and sell. It's a bit cheap a method, but really, as I said in that thread, it's a tool, right?
If these were cheaper, even Pepakura would be outdated! :lol