Currently I would simply like to find all files that have not been modified in the last X days but ultimately I would like to be able to make more complex queries against my sub
there is no repository query language or search api. for complex queries, you would need an repository indexer (like http://supose.soebes.de/wiki/supose) or a commit database (like http://www.viewvc.org/). http://markmail.org/thread/wszzgnrny6o2r7u7 has some more links.