I live in Ohio, and I have an interest in assembling such things.  I don't think we'd have much of a market though.  I can't see making new receivers, no doubt a very costly endeavor.  The major ammo manufacturers ignoring the 30-40 would be no help to marketing.  Trying to sell an original can be a challenge once the prospective buyer gets digging into ammo availability.  No doubt someone has a bunch of receivers that would mate up with your parts, but who?  Numrich?  Due to BATF decisions, their receivers have to go to a FFL.  Oh, paperwork!  What's it take in the way of a paperwork (with the most important paper, money) to be a firearms manufacturer?  Making a truly sellable Krag would require craftsmen, I'm just a bobba with a pipe vise and wrench.