A startup out of Canada is launching a product that takes in several different color filaments and splices them into one filament that gets fed into your printer, enabling some level of multi-colored 3D printing through one extruder. And all for the price of a small printer ($475)! I've been watching their development for a few months and their blog is interesting to read. It would be nice to print in multiple colors easily, but $500 nice?
The samples pieces they've printed look nice, but conceptually I can't see how this will create anything but a long fade between colors. Who knows. It would be awesome if I'm wrong.