We've decided to go an alternative route with out mailing list... I know it hasn't been updated at all lately but we're currently seeking pans other than major site updates for it (or perhaps a secondary list).
Instead of using our current CGI platform for our mailing list (which takes ages to send mail) we're going to start using a PHP/MySQL mailer. This will not only mean more speed, but it'll also mean easier administration and a better way to mail users.
If you have any input on mailings (or lists in general) please feel free to respond to this posting.