Quick and dirty rebuild of list messages

I want to rebuild a mailing list based on the gziped mbox files I've downloaded from the list archives. The messages aren't TO anyone, and my mailspool is in Maildir format, so I think the easiest thing to do is just formial -s the file and dump it into a Maildir folder.

Do I HAVE to create a simple procmailrc file to feed the command line or is there a way to just pass ".folder/" as the destination on the command line?

formail -s procmail -m rcfile < mbox

does something like 

formail -s procmail -m "`echo :0\n.folder/`" > mbox work?

(The reason is I actually want to automate this, and it's a lot simple if I don't have to create an rc file).

-- 
Belief is one of the most powerful organic forces in the multiverse. It
may not be able to move mountains, exactly. But it can create someone
who can.