Okay, on the surface it seems easy;
I just want MH to interface with the local message transport system (is that
the correct terminology?) the exact same way /usr/bin/mail does.

Here's the problem.  I send mail to "vax".  I am not hooked up to the network.
I do not run a named.  This is what happens:

--Q-ID-- --Size-- -----Q-Time----- ------------Sender/Recipient------------
BAA00204       14 Fri May 31 01:11 <vax@linkdead.paranoia.com>
                 (host map: lookup (linkdead.paranoia.com): deferred)
				   <vax@linkdead.paranoia.com>

I assume this is because the VRFY command to sendmail is returning the
fully qualified username, but I don't know why anything is paying attention
to this.

Here is the entry in /etc/hosts, as you can see no lookup necessary:
204.145.225.245	linkdead.paranoia.com

"hostname" returns the FQDN as shown above.

Here is my mtstailor:
mmdfldir:	/var/mail
mmdflfil:	
hostable:	/usr/local/mh/lib/hosts
servers:	localhost
sendmail:	/usr/sbin/sendmail
clientname:	linkdead.paranoia.com

My MH config file has "sendmail", NOT "sendmail/smtp", since that was 
giving me VERY bizarre behavior I was at a total loss to figure out
(dumping my mail to the gateway on a network I connected to _last_ time,
 as opposed to the network I was currently connected to, with hostnames
 all mangled and concatenated strangely as heck)