Random, css-classes??

[Luggruff]

Is it possible to randomize css-classes?

I want to use a banner for my forum as a background-image using css.. but i also want to be able to randomize it. Not using random css file.

-I want to be able to choose a table or any tag for that sake wich I want to use random classes in.
-The classes that I'm gonna choose from are the ones in the style manager.
(example: .tcat, .thead, .input)

Anyone have a clue if it's even possible?
And if so, anyone think that they might be able to pull it off?