The Powder coater in Wiveliscome Somerset I was talking about on another thread does very good work, my bro is into his BMX and one of his friends had a very expensive BMX frame done there, aparrently the finish was 'better than factory'.
Being Wiveliscome (and therefore a bit like heartbeat but with modern cars) they haven't got a web site, but I would be happy to arrange to receive the frame and return it to you once done if you can't find anyone local. Oh! FYI they media blast the frame first. £45 all in.