Please have the answer to my question! Our Jaguar Server boot partition ran out of disk space last night--coincidentally (?) just before our RAID data volume died. I replaced the RAID volume with a new drive and moved the AppleMailServer database from the boot partition to this new drive to free up space on the boot drive (using the Apple Help instructions: shut down mail server, mv AppleMailServer folder via Terminal, replace with a symbolic link to the new location, turn on server)... Except all the old IMAP mail is gone. I logged in as IMAP Admin and indeed it doesn't show up; inboxes are completely empty.
I can see all the old account names under AppleMailServer/AppleMail/User Accounts/, though they each only seem to contain a too-old Inbox. There are files in the MailStore folder dating back to January 2003; and in the AppleMailServer/Unknown Users/ folder I find, seemingly, Inboxes dating from two days ago that theoretically should be the right ones. Except one user's name is not appearing in this folder, and he did lose all his mail.
We still have a copy of the old database from the last mail backup (which runs nightly via the shell script from afp548.com that shuts down the mail server, rsyncs the AppleMailService folder, and turns on the server again), so this should be a kosher backup. Any thoughts on how to actually retrieve the mail out of there!!?
The reason I mention that our RAID volume crashed is because we had a number of shares on that volume, and am wondering if having to rebuild it to a different device somehow messed up user accounts...? Not plausible, but with OS 10.2 Server...
We're also planning to upgrade to Panther Server, if that would help us recover the info.