Interest in database-based email?

Hi all;

Just as an anouncement, I am working on developing a PostgreSQL-based
mailbox driver for tpop3d (a GPL'd POP3 server).  My general plan is to use
this as a connector to the email components for my CRM software (HERMES).
Eventually I will be adding IMAP and SMTP support as well.

Do people see a need for using databases to store business emails?  In my
case, there is a definite need, but is this something which has a broader
appeal?  If calendaring and todo support were to be added (RFC 2445-2447),
would people see this as a viable replacement for exchange
(PostgreSQL/Email/LDAP/iCalendar)?

Best Wishes,
Chris Travers