Opposite problem here.

Can't find a business co-founder, I'm a guy that likes building stuff but has no ideas.

Part of my problem as well is that I use different tools to rails, mainly ASP.NET MVC etc.

You mention "The project is music related, Ruby on Rails + significant Javascript" but if you already have started coding why are you looking to hire a developer?

I've read alot around the subject of business focused co-founders seeking technical co-founders (mainly so I could know where to "be found") and are you offering just a salary or low salary + shares?