Mailman with IMAP/SMTP Account?

Hi all,

I'd love to be able to set up discussion lists that are maintained locally but are high-availability and without having to worry about spam blacklisting.

It seems to me that it should be easy to do this using an IMAP/SMTP account hosted anywhere, hooked into something like GNU Mailman, so that as email arrives it's processed and re-sent outwards again.

However, most of these systems seem to assume that you're running an MTA or other mail server software locally, instead of running as essentially a scripted client. For example, Mailman accepts mail only through LMTP, though it looks like it can send at least using SMTP.

Can you hack Mailman to use an (IMAP/POP3)/SMTP account, or does a discussion list suite exist for this? Or do I have to write one myself (ugh, coding email apps?)? :)

Thanks!