[Dovecot] user database clarification

[Jared]

Hi, this question gets back to a thread I started back on July 8th.  
(gosh how time flies)

I still am not clear on why PAM is not supported for the user database.

I'm in an environment that has users both in local flat files 
(/etc/passwd and /etc/shadow) AND in an LDAP database.

Is it possible for this set up to work with dovecot?  (both local and 
ldap users have imap/pop?)

I'd prefer to just have Dovecot use PAM for user db and the password 
database so that I can configure PAM to try both local users and LDAP 
users.

Thanks a lot.
-jared