I don't know anything about the largest quilt shops anywhere, but one tradition I have anytime I go on vacation (or out of town with my husband for his work) is to find a locally owned quilt shop in that town and buy something from there. All I have locally is Hobby Lobby and Joann's, and I know everything they have. So it's nice to find local shops in different towns and take home a "souvenir" from my trip.