as I did, you might also wonder if mailman is capable of running on multiple domain names with a single instance.

yes it is, easy. configure mailman for your default host and for the next ones, just add the following line to /etc/mailman/mm_cfg.py

add_virtualhost('lists.yourdomain.org','lists.yourdomain.org')

add a vhost for your webserver to point http://lists.yourdomain.org to the mailman. nicely you can add now (with the sooperdooper password) new lists via webif.

now the wondering point: your new list will still be listed on the webif of the default mailman host. I tried to patch mailman, as I remembered it was not a feature offered upstream. by reading the code, I just wondered, that there is a comparison alread done if the list belongs to the web url. well, all you need to do is changing the web_page_url variable of your new list of the virtual domain, because by default all new lists belong to - who guessed - default host. easy thing:

bin/withlist -l -r fix_url listname -u lists.yourdomain.org

well, now it just shows up onlt on the webif of the vhost it belongs to, ez, eh?