Hi Michael
I'd love to have sth. that tightly integrates the ML with the Bugtracker. In short: Bug sent to ML We hit a button and have an issue filed or rejected etc.. Meanwhile we can still discuss it via the ml. Once we have fixed it the mailinglist is notified automatically.
I implemented few times Request Tracker http://bestpractical.com/rt/ which
has excellent processing of any incoming mail - it sends back confirmation with issueID assigned in subject line. Ad status can be changed easily. Implementations works well for any incident response - problems can be (by means of queues with dedicated mails) - and it kees history of commnication well. But I would be a bit careful, if it lives well with mailing list, it is more issue resolution oriented.
Other option would be Fogbuzz http://www.fogcreek.com/FogBugz/ - I have no personal experience with that, but I follow Joel Spolsky thoughts for a while and I really like his approach. The solution is paid but they have some chapter Academical and Non-Profit organizations there, so this might promise some better conditions.
My proposal would be to send them an e-mail, describing your wishes and see, what will happen (e.g. your request will get lost in their automated filtering system and we are done with this option).
Jan
PS: One of my former clients was crazy about speed. Dream solution he was asking for was program with just one button called Quick. Push it and have the work done within few seconds. Once I implemented it (partially).