Now, I'm not high on crystal meth or anything, but I'll just assume for a moment that we all want better accessibility for the newcomers (even with the rise in volume that they bring), and that all agree to go with solution 3 :-). Thus I'll try to outline a battle plan:
Well, my own opinion is that this is aiming for perfection where the last 10% just isn't worth that much.
Simply setting up a stock forum program somewhere, doesn't even have to be on the HQ servers as long as it has an official looking address, would be have a good effort:reward ratio, whereas writing some new forum/list interface software would not.
I rather think you'd find that part of the reason people like web forums is that they do offer a lot of features that a pure mailing list doesn't .... eg the ability to have a buddy icon, a personal profile, etc. If you start from scratch you'd lose a lot of that and then wonder why not many people were using it.
Look at it this way. There have been unofficial Wine forums before. People already discuss it in distro-specific web forums. Yet, wine-users is not dead, we are not suffering badly due to split resources, and I don't see developers (well, except me sometimes) going onto these forums to talk to people. So we appear to have nothing to lose.
Single sign-in etc would be nice but it's _not_ essential and given the choice between another account (really not that bad given the N^2 we all already have) or not having some official forum, I'd go for the former.
thanks -mike