This was a very, very good idea I actually realized it after reading your post & started few experiments. After a while I have found that the toon shader was just the thing I was after. It really opened up a completely new level of thinking about the model coloring & design for this game.

I have made a few modifications on spiders with standard Toon shader from GS 7.84, here are some screens..













What I need is few toon shaders, I was thinking of trying out different things and maybe even have older & newer shader versions so that even older computers can process the whole thing.