Unless you're bent on doing it yourself... price powdercoaters. I work for a security door manufacturer and we do our own paint, but send out for powder, he charges us $75 a door. Granted, I don't think that is his retail price, I think it is $100 for his retail customers. Before you say a frame is much harder to powdercoat, consider a door with perforated steel for the screen... that is much harder than a bike frame! Imagine getting a proper coat inside each and every one of the 1000+ holes.
I'd rather pay an extra 50 bux for a powdered frame. I think all frames should be powdercoated.