Faking Hairs With Onion Layers

[starbucks]

Hi guys,

I'm sure this topic has been developped on those forums, but I couldn't find anything after an extensive search.
I'm looking for a way to generate texture maps from hairs, at different depths inside the hair's volume, exactly like they did on Shadow of the Colossus for PS2, check it out :

http://edusworld.org/ew/ficheros/2006/pagi...ng\_of\_sotc.html

basically it's a bunch of onion layers, with different maps and transparency, that simulates the hair thickness.

Any ideas and methods are welcome!! Thanks in advance.