I actually got an idea. How about making the size of the brick relative to small actual bricks. Basically the model itself would be way off the center, each body part having assigned a 3x3FF brick, stacked onto eachother the right order, you would get the minifig, each 3x3FF brick coloring a separate part. I remember I did the same thing with a vase, I had the vase itself and also had another brick on top, but it was actually in the vase (the water).
This might be a bit difficult to be done though, and not sure if that worth it either.
