I've seen one and I was less than impressed by it...
Reason being? The powder coat was on EVERYTHING, the lower and upper appeared to be dipped then had it's powder coat baked.
Don't know about you, but I'd prefer not to have the powdercoat inside my upper receiver or for that matter have it on the rails of my receiver just so that the tolerances would be what they are meant to be.
Only benefit to having the powdercoat inside the upper receiver that I could possibly see, it would make cleaning a breeze as carbon fouling would be easy as heck to spot and probably wipe up easily. Still though, don't like the idea of it.
Looked cool from the outside when looking at it on the gunshop rack, but when I had it in my hands and cycled the bolt it suddenly lost some of it's appeal.