I think Kobun lives in Norway. He hasn't posted for a long time, but i think he still lurks every once in a while.
#1 No, the Neostead isn't imported to the US. Reread my post further up for more info.
#2 I vaguely recall Springfield making a civie legal version of the M6 a while back. I don't know about the bolt gun.
#3 Not unless you can find one that's already registered as a transferable NFA weapon, and it'll cost you more than your soul is worth.
#4 The Robinson Arms M96 Expeditionary Rifle is basically a semiauto copy of the Stoner M63. They don't have a beltfeed mechanism for it yet (the're working on it I guess) and, unlike the original M63, it takes a standard AR-15 magazine rather than a proprietary one.