iPhone: what's the best way to create disco-type spotlights?

I have a character that I want to light up using 3 or 4 spotlights with different colors. I want the colors to mix and tint the character as they move.

I am trying with projectors lights + blobs... but I can't figure out a way to make it work. Not sure either what type of Shader the character should have in order to make it look good.

I need advice, Thanks a lot