Simon Hanna writes:
Actually mailman-core is fully functional all alone.
That's not really true. Sure, you can telnet to the REST port and speak REST by hand, but that's hardly pleasant. At a minimum, you need mailmanclient. (There will be alternatives, there was a GSoC project to provide a client that integrates with Node.js. But at the moment that's not production-ready.)
Also, all this talk may be somewhat premature, as at present there's no authentication in the REST protocol, so everything needs to be on the same host. Andrew Stuart's authenticating proxy will help with that, but AFAIK it's not integrated yet. It may be worth waiting for that (and/or Mailman 3.1 with the migration story) before doing betas of the Debian package(s).