This is still a work in progress but the MakerBot actually seems to print braille rather well. I can't read braille so I can't judge for sure whether it's readable but it certainly seems like it. The trick is to get the G-code right to prevent warts on the front face (i'm still fiddling with this).
I think this might have a lot of potential. A braille bracelet will be next in my printing/designing queue.