I do a bit of moonlighting for about the price range you listed - though it's not in the skillset you mentioned and amounts to just a couple hours a week. The thing is, though, that it's mostly a maintenance project with some customized development here and there, on a project that I was working full time in the not too distant past.

I don't know that it's possible to get moonlighting work on a project where you're coming in from the cold. Most of the opportunities I see along these lines are either where I have some specific knowledge of the business domain, or where I've worked with the company/people in the past.

My suggestion would be that if you have some software projects or people you've worked with in the past, you might call them up and see if they need some touch up work here and there. The companies will be happy to have your expertize without having to pay you full time.