I have a friend whose son was born with a partial hand. They were able to use 3D printing to make a prosthetic that was cheap enough they could make new ones as he grew. IIRC, they could do themes such as iron man for the prosthetic.
I love it! In some ways these printers are only begining to exit the novelty phase (I mean the consumer versions) and already there's a minor explosion in exiting uses for them. An exciting time!
Do they have photos, video or info to share? Would be really interesting to see it working, sounds awesome.