[LUNI] virtual mail users

[sten]

Hey, all; 

I'm building out a new shared node for my personal domains; on the old node, I've been using Cyrus IMAPd, which gives me virtual users and a central mail database. I've had a few issues with Cyrus locking mailboxes, causing mail to be rejected, so I'm thinking I might like to try something new, but I really like not having all my mail in ~/, and not having to create a login account for people that I provide mail service to. 

The only other option I've seen so far is Courier or Dovecot writing to a MySQL database, and I'm not terribly thrilled at the idea of relying on MySQL for mail delivery. Anyone got other suggestions, or rants/raves about dropping mail to MySQL? 

Thanks!
-sten