Ooh, that's an interesting idea!
All image/css assets come from an assets folder in the subsite (so either http://main.domain/sitename/assets/... or http://vhost.domain/assets/...)
If I put in a request handler for those I'd bypass a fair bit of code!
(at the moment we have a gcms-mount package mounted at "assets" in every subsite, with an index.vuh which does the serving from the content repository)
(or, as you suggest, it might be possible to set up nginx with a rule to cache */assets/* ?)
Joe
