Color Randomizer map

I'm trying to find a way to write a script for a map where someone could pick a few colors and apply them randomly to elements. i.e in the diffuse color.

This could come in handy when trying to variate wood planks' colors or concrete casts etc.

i've recently tried experimenting with vrayscatter and noticed that the vrayscatter tex does excatly this job "on proxies not geometries".is there something similar to this that wouldn't require me to buy the plug-in?

i've tried snooping around but couldn't find anything to suite my needs. please notify me if i've missed something.