Hmm, I'll think about the mat zones idea.

If the skirt were an actual wrapped rectangular piece, it would be easy to set colors depending on the u- or v-coordinate. Actually wrapping it would probably be a bit too difficult for Poser's cloth simulation, but I could try wrapping it and then cutting off the pieces not on top? I'll play around a bit and see what's possible.

If that doesn't work, refer to the top of this comment. :-)

-- I'm not mad at you, just Westphalian.