A nice idea--but I don't see that even IF the 86 ban went un-constitional (I doubt Heller will touch on it--but then again I said the SCOTUS wouldn't hear the case AT ALL--so what do I know) there are VERY strict de-mil requirements in place. Remember, the CMP's rifles are named by type in federal laws that allow them to be released for sale--but the DOD can just say--'no' anyway. A culture shift that might come with a sweeping ruling might help, but it would be a long stretch to see mil-surp class III's.
Besides---although I would (more and more) love an old triagle-handguarded 16-a1 just for the clean lines it offers next to the m-4, they were made by the lowest bidder---and MANY of the 80's-90's 16a2 JUST PLAIN SUCK in terms of quality.
Anyway, it is a nice thought.