If you used Dovecot's deliver, the deny passwd should have worked, but I've no idea about procmail.
I'll note that I'm using procmail because of the ability to filter and run SpamAssassin from it. Does the Dovecot LDA provide the equivalent? (I know there's Sieve, though haven't looked into how one uses it.) If so, how hard is it to migrate my procmailrc files?
