You can also try the store in Disney Springs. I think the store is the Market Co-Op. The dresses and accessories are in the back of the store. Another sections sells prints, and the area connects to Tren-D.
Some dresses are also sold in Hollywood Studios along Sunset Boulevard. I think the shop is called Legends of Hollywood. It is on the right side of SB, more towards the Center Stage/Brown Derby end of SB.
I can't say for certain, but I think the selection in each location varies a bit, but with lots of overlap.
I want to say I also some of the dresses in some hotel gift shops, but I can't say 100% on that, and if so the selection would be limited. The also sell a limited selection online.
!
