You could try Erlibird - http://erlibird.com. The crowd is typically less technical than HN readers, in my experience.

The problem with such a site would be attracting people with expertise and experience who would be willing to use such a site.

Show HN works because HN is one of the 4-5 sites that those people use daily anyway, another site would be unlikely to be able to attract the same crowd.

Ideas are cheap. Execution is hard.

If you want advice, ask people you don't know. Friends will always tell you that the thing you're building is cool because they're your friends and that's their job. Strangers will give you cold, honest feedback, and that's what you need.

It's a good idea, but don't you think people would be afraid giving away their ideas? I'm not a believer in the "non disclosure" approach, but still think that asking wide open would still be too intimidating for people.

I think the benefits of getting valuable feedback outweigh the risk of someone stealing your idea.

I found erlibirds.com , is that soemthng you were looking for?

http://betapunch.com gets you one real user to record their experience using and talking about your website.