Call Accuracy Ordinance in Winder, GA. They did a Model 41 and I think they could do something on the 22A. You really should just consider selling the 22A and getting the M&P22 pistol. It is already threaded underneath the barrel nut.
Ive done one, its no different than any other 22, except for the huge fact that you have to cut your top rail back to the last screw. Ill see if I can dig up a pic of it...
There it is, it was for a buddy who obviously didnt want to spend much money on the threading on a $100 gun, so I didnt spend much time making the thread protector look any good.