(Yes, "individually themed" is an oxymoron, but I still want it.)

I've just moved from Windows to Ubuntu Linux, and although I am enjoying this new adventure playground, I've encountered something quite unexpected... and its bugging me.

It is probably because there are so many gnome apps in Ubuntu (... how strange :)
This is great. and the range of available apps is excellent! ...but because of this one-stop-shop scenario, most of the windows look remarkably similar.
I'm certainly not after bling-maximus, but I would like a few differentiating colours for my not-so-young eyes to help identify an app at a glance (especially in the compiz lists) ... I love compiz :) I thought it was just a bit of razzle-dazzle, and that alone would be enough, but it is actually very practical to boot.

So, basically, I'm wondering if there is a way to theme individual window components on a per app basis... especially the window decoration; menu bar, etc.

Thanks.