For those that don't know it: we've played Nomic before. It kind of failed due to lack of good initial rules, I think, leaving it hard to stay involved. I might be biased though, I was host (eg I kept track of rules and gamestate, though I also played), and it's a fuckload of work - whole lot more than WW.
I'd personally go for a more thematic Nomic, like what happens in the BlogNomic Nomics. It's currently on some kind of farmer theme (EDIT: it might be Plants vs Zombies in a second look), but I noticed Harry Potter, poker, even Lego on there. The barrier to entry is quite high though, otherwise I'd be playing there I think. But since they're going for 8 years straight now, it seems they are doing something right.
And I don't think it's really necessary to make a distinct forum - we could go with a few threads clearly marked as belonging to the Nomic game, maybe coupled with some scripting or an external website if there's things we can't easily do on the forum.