I vaguely recall one that used different colors of bricks in stacks that determined things like armor, strength, ect, but I'm not really sure what it was called... I'm looking for it now, but it's not showing up, really. You could always just go with Brikwars, chapter 7, though. Oh, I wrote up a Biowars supplement a while back too! I'll see if I can find it, it never really got past the extremely early development stage, I think I play-tested twice...
Edit: Here's my attempt, it pretty much needs a complete overhaul, but feel free to use it: Biowars 1.2