Lost-wax casting is the the thing that makes me interested in 3d printing. Hopefully in the next two years or so I'll have the space and budget to set up a small casting and milling operation for making my own guitar parts.
Also I'm wondering about the environmental ethics of burning off a big chunk of plastic. For proof-of-concept it's probably fine, but imagine if this guy does this kind of thing on a regular basis. If we could invent a 3D printer that prints with wax it would be actual lost-wax instead of lost-plastic, and a lot healthier.
I was just talking to a friend about his the other day. Sort of. He said it would be funny to take people's fetus sonograms and make models of them. I said it would be better make the models into candy molds.