I just enabled /etc/passwd accounts on my toaster.
For anyone considering doing this, the process is:
[list=1]
-  Set vpopmail_etc_passwd=1 in toaster-watcher.conf
 -  Re-run toaster_setup.pl -s vpopmail.
 -  If you previously had your local domain set up as a vpopmail domain (as I did) then:
[list=a]
        - Create /etc/passwd accounts for anyone who needs to receive mail in the local domain.
        - Add the local domain to /var/qmail/control/locals and remove it from /var/qmail/control/virtualdomains
        - Create appropriate aliases in /var/alias for root, postmaster, and mailer-daemon, as described in LWQ.
        - svc -h /service/send (causes qmail-send to reread the control files and pick up the new configuration).
        - Move mail from the virtual maildirs to the user maildirs
        - When you're sure everything is working, vdeldomain localdomain (removes the old virtual domain)[/list:o][/list:o]
So, mail delivery works fine, and I can read mail using command-line MUAs, which was the goal.
However, I can't seem to access the /etc/passwd accounts using IMAP or POP3.  I'm using the courier POP3 daemon.  I rebuilt courier-IMAP but that didn't help.  Any suggestions? 
			 
			
			
				If you want to use system accounts with courier-pop3 or courier-imap, you have to add the following to /etc/pam.conf
imap  account required        pam_unix.soimap  session required        pam_permit.sopop3  account required        pam_unix.sopop3  session required        pam_permit.so
Thanks to Matt for a nudge in the right direction on this.