I know this is way to far for this feature to be even considered I am just floating this idea to track some interest from others. I came across "Mimaki USA" who have developed Multicolor 3D printing successfully . Their 3D printer achieves 10M colors to be printed on the model. I guess there is an additional head to paint the surface after each layer is printed. I am not sure where to start this from may be some one can drive this feature ?