As far as turn-around time goes, 1 minute would be nice. :)  The FreeBSD
list turns around my messages in about a minute or two, and I believe they
run mailman.  

I have a big beefy ezmlm box that I could host the list on, but the future
of that box is uncertain as of now, and it may be replaced with a different
system that would be incompatible for our purposes.  

I think the reason ezmlm is so much faster than mailman is because it uses
the Maildir format instead of mbox.  I haven't looked at the mailman code at
all, and I'm no python wizard, but how hard would it be to hack in some
Maildir type support?  Or what about some sort of hashed directory structure
like the qmail queue, and have each message get it's own file?

Jay