[mpfefferle]

POPFile has an IMAP module that makes something like this pretty easy to set up. You just need to connect POPFile your GMail account, set up some buckets for POPFile, and then tell it how to map those buckets to IMAP folders.

It takes a little time to train the filters, but once that's done, the accuracy is pretty good. My only problem now is coming up with a good labeling system.

[jgrahamc]

Yes, it does, and for power users they can certainly go that way. Although, POPFile doesn't support OAuth for IMAP at this point so you have to trust your configuration with your GMail password.