Well, I get the feeling Sasuke got some of his current shirts from purchasing at that cat lady's store where the Uchiha frequented so often. As for the years during the time-skip I guess he just sewed the crest onto it himself. Shouldn´t be too hard with as much pride as he´s got in his clan.
I never saw the crest on Itachi's back after the massacre however, so he might have thought his Sharingan was enough to distinguish himself as an Uchiha. And Madara had likely packed quite a bit of Uchiha robes before defecting. I´m guessing Obito made his own robes, as he probably made his masks himself or had the Zetsus help him with it as a way to pass time hehehe....
