Have you seen these?:
* "Ball Princess Usagi-WIP", by Sakinurai (See: [link]
* "Happy V-day Usagi", by Sakinurai (See: [link]
* "Ball Princess Usagi- Colored Variations", by Sakinurai (See: [link]

You might also like these:
* "Imprisoned Usagi- CosplaySketch", by Sakinurai ([link]
* "Serena Dressed as Neo-Queen Serenity", by Sakinurai ([link]

Will there be any pics of BRAVE's Princess Merida for you Disney Princess pics?

Have you seen CorinnaFaye's "Sailor Moon - Planetary Princesses" (See: [link]?

In reguards to the idea of artwork of Usagi in the dress Prince Demando dressed her in while she was held captive on the Black Moon:

* "DM - Princess of Darkness Sketch", by Wildnature03 (See: [link]
* "Moon Usagi", by Sakinurai (See: [link]

Hope they're useful.