I didn't like the official saturated, dark red hair so I modified it to look more like a lighter chestnut shade, looks much more natural in my opinion. (Apparently a bit more book/lore friendly too)

-FILES-
Within the Zip is:
Hair_Red1.xbm
Hair_Red1_n.xbm

Just place the Cooked PC folder into your Witcher 2 directory. You only really need the Hair_Red1.xbm for the colour, I haven't modified the Normal maps, but they are there just incase you need overwrite something.