I was thinking, would it be possible to make a fan-made positional gun like the ones used in Terminator 2? Those things are likely to one day end up like the Star-Wars yoke; no-one makes them, but everyone wants them. I was thinking though; suppose you bought say, a toy Uzi made of plastic. You could modify it a little using some clay and then make a fiberglass mold. From that mold you could make the actual gun out of fiberlgass and sand it till it's smooth as glass (minus the fiber). You could also have a hole on the side for the "missile" button on the side, which shouldn't be too hard to find. The trickies part would be how to go about jointing it and all that, because you'd probably have to machine the parts. Also, figuring out where and how to mount the pots could be tricky. If you have a positional gun I'm sure it would be easy to take one apart and see how it works. Also, it would need a good black finish.
I think this could be a really neat project for someone who has good fiberglass molding skills and knows where to go to have the metal parts machined, and hopefully it would turn out well enough to be a saleable product if they could be produced quickly and efficiently enough.