Hunter-
An email-bbs bridge is absolutely the best of both worlds. You get structure of a threaded system + emailability for conservatives.
There is already a fairly convenient web interface for *reading* the mailing list at gmane.org. However, we need to have some protection against posting to it from a web interface, so as not to be drowned by spam. If we want to provide such a gateway, it has to use the same or a similar authentication procedure as the mailing list -- just being authenticated by your Wikipedia account would not suffice, because the Wikipedia account itself is not authenticated.
If you wish to provide, or are familiar with a web interface that allows *posting* to a mailman-based lists with authentication, then yes, that would be an option.
Regards,
Erik