Dbmail is the name of a group of programs that enable the possiblilty of storing and retrieving mail messages from a database. Currently MySQL and PostgreSQL can be used as database backends. The experimental 2.1 version of DBMail also supports SQLite, an embedded SQL database system. Development and support of dbmail is done by IC&S, a Dutch company specialized in Linux development and support. The dbmail developers can be reached through the dbmail mailinglist.
Sounds appealing - I have so many email files in various places and some of them are so large it takes many seconds for email clients to read them. Would be nice to have everything in one place, with the performance benefits of a database to boot.
Dbmail
http://www.dbmail.org