I have purchased an gun and did some work in my oven, however the results were mixed. The problem I ran into was consistency in the finish. The idea of melting plastic over metal seems simple enough, but the surface needs to be preped properly.
I eventually sent mine out to procoat in Vancouver WA. The sand blasted, and pretreated with iron phosphate. I've had no problems with peeling of finish since.
He did my intake and inter cooler pipes on my 951. It is a near chrome with a clear over.
Geoff did these as a favor, but I know the do all kinds of auto stuff, I've seen rims, and even car frames.
http://procoat.us/index.htmI bet that as a group if there was enough work you could get a volume discount.
For small pieces, I'd just do those in my oven, but anything with multiple coats or that has contact with oil, it might be allot easier to send out.