Hi @GalacticGal I don't know if you tried Littleberry's s4s site but, it is working for me. (media fire) you may need to register to download if you are new but, registration is free.
http://sims4studio.com/thread/2924/littleberrys-rococo-corner
You will need to download this dress for the mesh:
http://mystufforigin.blogspot.pt/2015/01/rococo-dress-conversion.html#more
You can try the direct page for the Antoinette gown:
http://simsdentelle.blogspot.com/2015/08/robe-antoinette.html
Other Rococo dresses:
http://simsfans.forumfree.it/?t=70453687
http://simsfans.forumfree.it/?t=70461449#entry571018214
http://simsfans.forumfree.it/?t=70461453
http://professorlilith.tumblr.com/post/131351520412/weeberry-sims-4-rococo-wedding-clothes
