I'm thinking of starting a social network for a certain type of partner dancing.

It's a niche I know is not currently being served, and I know there is demand for a comminuty site from consumers, and probably suppliers looking to contact those consumers.

I've made websites, but am new to making social networks.
This would be a hobby, that I wouldn't have to much time to spend on.
I was hopeing to buy a domain name, spend say 20 hours setting up a site, seeding it with some starting entries, then just tell the consumers, and hope it very slowly grow of it's own accord - there's no hurry from my point of view.
Is this nieve? bearing in mind the known demand.

I'm currently considering a pre-built solution like Spruz.com or a hosting the network myself using something like Elgg.
Anyone have any comments as to the pros/cons of these 2 paths?
Any better solution providers?

Thanks, Avanti