whats funny is that there are actually 1911/hi-power/lugers/broomhandle mausers that are exempt from the NFA with "original" shoulder stocks. No tax stamp needed. They would be 12020 legal, but would probably violate 12276.
I know that DrDremel SBR Form 1'ed a C&R Sistema 1911 in MI. And making a shoulder stock that wasn't skinny where it attached, but was tall enough to cover the entire back of the grip would eliminate the "pistol-grip" grasp. Wouldn't work good for a 1911 with the grip safety, but on a hi-power, why not? How much do C&R Hi-powers go for?