This is a really cool new extruder, coming out of Italy, and on show at the MakerFaire in Rome this week. It's called the Multiextruder NPr2 and it can print in up to 6 colors per object. The company, 3DMakerLab currently has their 4-color version working, but the 6-color version will be coming soon. It should be released for purchase by December (2014). Read and see more at: http://3dprint.com/17072/multiextruder-npr2-6-colors/