Still like the bullet belt concept, but yes of course probably alot involved. Though, if you were planning on doing the strap like that, then it would probably be overkill. If I had to choose between the guitar sides and the strap for bullets, I'd choose the guitar as that has probably NEVER been done before.
I've never paid conchos any attention... my personaly opinion would be to avoid them though. Concho just sounds cheap. If the guy is paying a good amount of cash for this, I'd keep everything as custom/authentic as possible.
Other than that Im afraid Im of no help. You could have indians scalping people somewhere! Yeah, I dig that idea.