[Dovecot] Track when user last checked mail

First off I've just got to say thanks. We just upgraded from UW to Dovecot migrating from mbox to maildir. Wow, what a difference! Load average used to hang around 5.0 during business hours and could get up to 20+ on a bad day. Now we rarely break 1.0!

I'm wondering if there's a way to keep track of the last time a user checked their email and whether they checked it using POP or IMAP. We're trying to gather statistics on what protocols our users use and find accounts that haven't been checked for a long time. We used to be able to do some of this with the finger command and the user's mbox. I found a script called "mfinger" that works better with Maildir, but it's designed for Courier.

Any ideas?

Thanks!