Attaching themes to taxonomy

Hello.

I am looking for a way (a module, maybe?) to associate certain sections of a site with a particular theme. I was thinking that a taxonomy would be a good way to do it, but I am open to using any systematic means of automatically use different themes for different sections of a site.

The idea is that within a portal there may be several web "sites", possibly with their own domain names and web stores. The idea of running these in one site is to provide uniform base functionality and search all the "sites" from one location. Think of it as a mall where every store is independent, kind of, but there are still uniform features pertaining to all the shops.

Thanks for your ideas.

Alex.