[Exim] Non root operation

I'd like to run exim as a normal user.

-First, I'll cover how...
-Create a user for exim
-Have exim run as a user mail.
-Provide exim capability to bind ports
lower than 1024. (via LIDS or something else)
-For delivery of mail, via maildir, give each
user a userMail group to which both the user
and the exim user belong. Set Maildir perms
to user.userMail, set g+rw, u+rw. Or, if ACL
support exists, just permit the exim user read
and write access to the maildir directory.
-For /var/spool/mail support, do the same thing.

The only problem that I forsee, is that exim
will still want to be able to assume a different
euid for delivery. Therefore, I'm proposing a
configuration option in the config file that lets
you tell exim to do everything under it's own user's
uid, and not change at all.

Thoughts?
Mathew Johnston