This is the store in Tomorrowland where you can purchase a Disney hat. With a large selection, including Mickey Mouse Ears, this could be an option for a hat that is less busy than the Mad Hatter shops. Hatmosphere will also do embroidery.
20% Off! Tinker Bell Light Up Figurine
25% Off! Children's Hooded 50th Anniversary Jacket
Wooden Disneyland Picture Frame
Sorcerer Mickey Antenna Ball