Creating Shader presets, but also considering randomizer script for such presets

EightiesIsEnough

I am in the process of creating shader/texture presets at this moment, but once that is done, I am considering creating a script that can allow me to assign the texture to the object, such as a building, at random, which will save me some trouble.  All I would have to do is select the object, and the surface I wish to change.  With just one click of a button, it can add the texture and a random diffuse color combination to the surface you wish to change.  This will save me a lot of work when it comes to retexturing the exteriors of buildings while updating my big city scenes.

Are there any tutorials on how to create a script to allow such randomization?