Vaders R Us

So last night when I was trying to sleep something occured to me. Unless Chancellor/Emperor Palpatine really forsaw the future in such detail...how'd they get Vader's helmet and costume done on such short notice? Is this standard rigging in the SW universe? Is everyone in the SW universe on a respirator walking around in a Vader helmet? Was there a catalog to choose from and young Anakin said, "I'll take the one in Black?" That's just really weird design to make on the spur of the moment. I really think they had to have it on hand.