Postfix dnsbl and virtual domains

[Jacob S <stormspotter@6Texans.net>]

Hello List,

I used the tutorial from the following site to setup Postfix with
virtual domains and a mysql backend on a server recently. But I have a
couple questions about ways to improve the setup.

http://www.workaround.org/articles/ispmail-sarge/

Currently, when I add a new user to the 'users' table in MySQL, Postfix
creates the Maildir "user@domain.com" in /home/vmail. Is there a way to
get Postfix to do it more like /home/vmail/domain/user for the Maildirs?
Obviously I would need to adjust the output from Courier's authdaemonrc
to get POP3 and IMAP to continue working, so any suggestions are welcome
there, as well.

I have the following line for smtpd_recipient_restrictions in main.cf:
permit_mynetworks,
permit_sasl_authenticated,
reject_rbl_client list.dsbl.org,
reject_rbl_client combined.njabl.org,
reject_unauth_destination

Is this going to prevent authenticated users from sending mail through
my server if their ip is in one of the dnsbls? My goal is to only
prevent the server from accepting mail from IPs in the blacklist if they
are not authenticated.

TIA,
Jacob