As of 2012-01-15, this can be considered a complete (in terms of what I
set out to do) and tested mail server implementation, so the project
will find its way to the "back burner" here. But there are still some
things I hope to accomplish. Here's a list of the unfinished things as
they stand:

1. Improve the complex queries, especially the Postfix access-rcpt.query
   and maps-transport.query. Also, figure out a clean solution for the
   problem of catchall domains and the recipient access lookup. I want
   help with this, which is one reason why I went ahead and announced
   the project: "more eyes on the bugs". :)

2. More "HOW-DO-I" examples in the wrapup. I thought of a couple others
   a few days ago, but I neglected to write them down at the time, so
   they did not get done. They will come back to me eventually. :)

3. Database management scripts. I'd like to have "mail-adduser" and
   "mail-adddomain" and possibly other scripts which will take input
   from the admin and update the database. I'm more an admin type than a
   programmer type, but I am not averse to some shell scripting.

4. Redo the schema without the obnoxious camelCase column naming scheme.
   Those names, being unique per table, helped me in writing it, but I
   think I have progressed beyond the need for that crutch now. I had
   decided to do this before finishing, but when I was close enough to
   being finished, I wanted to just get it done. IN PROGRESS: SEE
   "new-schema.sql"

5. The Transport and Alias tables are weak. They would be better with
   more integration to the rest of the database. For example, the
   Transport.tpNexthop column should be a pointer to a row in the
   Domain table. Alias.aliasTarget could be a pointer to a row in
   Address, just as VAlias.vaTargetNum is. There would be challenges in
   doing this, but it is doable. Again, I knew this before finishing,
   but I wanted to get it done. IN PROGRESS: SEE "new-schema.sql"

2012-01-16 update: all of this is going to go into a complete rewrite.
Thanks for your interest, and be watching for release announcement of
the new document and files.