Well, even the skis in the game start in your hands as blue, only changing once made into vehicles/coloured nodes on your body.
In BL0002 Badspot used setSkinName and a lot of bitmaps for both painting and weapon colouring. Here, in Retail, he uses a colour "ID" system for painting and ColorShift for the weapons. I don't think it's possible without a lot of changes to the painting and engine-side ColorShift system.