Whoa whoa WHOA! First you say I can afford a lawyer and then your calling me a "upstanding citizen"??? Who do you think I is?
IF you do not want to fit a 16" barrel to your 1911 (they make 'em, and some make 'em CHEAP!) then you would NEED to make it a SBR if your going to put a stock on it.
The only other way is if the pistol is a C&R and was mfgr'd with the butt stock (like the fancy officer Lugers and rare 1911's from WWII), then it is "accepted" by the BATFE that they are to be used in that fashion. But the chances of your C&R being one of those prized heirlooms is rather slim.
If you have the desire and the extra $200, just fill out the Trust stuff and ATF forms and go for it. What is the worst they can do? Say no and send you check back?
BTW, making it a .22 won't circumvent the SBR thing.
Pistol + shoulder stock = SBR,
also, pistol + 16" barrel + shoulder stock = legal,
last, rifle - 16" barrel or OAL< 26"(?) = SBR or illegal configuration