You wanted an Art community and it doesn't get any better than deviantart.com in terms of sharing work, discussing art and getting feedback. Artists can even sell their work and I'm sure a lot of deviants have gotten work simply because of their portfolio on deviantart.com.
No, I was wondering if there was something like, or conceptually analogous, to Y Combinator [http://ycombinator.com/about.html], the start-up funding/mentoring/development thing, not HN|news.ycombinator.com