A terrific idea! As JohnFitz said, this would be ideal for some of the more esoteric subjects we all love to build. For instance, a Parabellum gun kit in 1/4 or 1/3 scale could have brass sheet already cut with the fretting, and all that would be required was to bend it 'round a form to create the correct diameter, solder it and install it on the finished gun. Same goes for the Spandau gun.
Wheels can be a problem area, too. The scratchbuilders can usually fabricate their own wheels, but there are those of us who know more than the average sport flyer yet lack the skills to build something accurate to fit our models.
I believe that Arizona Model Aircrafters has been attempting to do this in recent years, but from what I've seen in their kits and the reports from modelers attempting to build their stuff, there is an awful lot of room for improvement.
Best of luck on this matter!
Lyle