I am a major power user of powder coating if yoou have read my previous posts on the subject. Have done many frames and engines and wouldn't consider anythig else, including catalyzed urethane paint.
As nosliw721 and others have said, it is a difficult process to do as a hobby. Not only do you need specialized equipment like a big oven and sprayers but you can't afford to keep abreast of changes in powder materials or stock everything you need. There is a shelf life to the powder.
I am a hard core do-it-yourselfer, even cast my own Chevy straight 6-cylinder manifold, but for powder coating, I defer to the pros. I look at it in the same vein as chrome plating. Sure ai could do it myself but why? Can't save any money doing it myself and I would do it so rarely that quality would suffer. Cost from a shop is not much more than it would be for a pro sand blast job on your frame and you get a great finish with the latest material technology.
Phat - LOVE the look of your engine compartment! Hope my 235 comes out that nice.