I'm in a similar situation, I've got a decent pool of apps running on the same framework that only differ in config and static files. The approach I took is usi

I'm in a similar situation, I've got a decent pool of apps running on the same framework that only differ in config and static files. The approach I took is using the ruby gem compass and sass. I moved any sass variables into a skin.sass file and that way each site can just implement its own skin file very easily with only editing a single file and not having to jump into the main css. This has made it relatively painless to create another skin for a new site. One issue I'm dealing with on this setup is that these skin files are site dependent and outside of the base code repo. They're in their own repo, but the issue is every site has its own files, so to add a new variable to the skin file requires adding it in 5-10 places, and that number is just going to get bigger. I'm curious if you guys have any suggestions.