Unfortunatey, color masks tend to look really awful except on things like spaceships -- because I'm using diffuse coloring, if you're familiar. That takes away any lighter highlights in favor of the color, which leads to a very flat, dull look. Very dark things cant be recolored at all with this. It would also be pretty hard to even extract pieces of clothing to mask from the movement dictionaries.
I see the appeal of the idea, and Keith and I have talked about it some previously, but I don't think color masks will do well for this game. Much as I'd like to increase variety!