I don't know.... with the post with the metal printer and the gun printer, it seems it's not that far-fetched...
Guns aside, I can think of lots of things this would be useful for.... make your custom-size Tupperware... drink containers, IPOD cases, phones cases, unique custom trophies for all sorts of events, fence attachments, Christmas toys, jewelry, glass frames, picture frames, sun glasses, dinosaur puzzles, lamps, molds, etc.
But I guess in addition to the cost of the 3-D printer, the materials matter...