Looks like the shortage is now extending to the SN95 boosters as well. 94-95 and 99-04 V6 boosters would work with some tweaks, but noe they are hard to find. Rockauto is doing a rebuild service only.
Almost all cobra brake boosters are made by Cardone. The other companies rebrand them and mark them up. I true Ford Cobra booster is really hard to find and the price is through the roof if you do.
I ordered mine from RockAuto. Paint it before installing or it will look like crap in little time.
I did the opposite, I put a fox booster {cardone) 54-73207 on my 1995 mustang along with a 1995 cobra master. PITA to make booster fit, did it because fox booster is a lot smaller, to make room for 460 swap. Brakes didn't work worth a damn, hard pedal poor stopping. Pulled 460 out after a year, put 302 in, changed brakes back to stock, sold car.