If anyone's curious about what phpbb (free forum software) might look like (you can change/customize themes), I put up a test board here. It literally takes minutes and I was curious myself as I haven't run one in quite a while, so.
It's got phone and tablet optimization built in now, which is nice.
Welcome to phpBB3 - Just a phpbb test
So getting a board and hosting it is at least not a problem. I can do it and I'm sure many others here also could and might be a better fit.
The only problem, as stated before but which I'll reiterate, is that even if you set it up on musicyack.com or whatever, there's probably not gonna be much influx of people, meaning the community will likely get isolated.