Okay, so since I was on such a gown-shopping kick, I ended up ordering one. It's:
5. From ModCloth.com
The bust concerns me a little, but that's why I went ahead and ordered it this early in the game: if I need to return it and find something else, I have time (but obviously reeeeally hope it works out).
So it's not full-length. That's okay! I think with the right jewelry and shoes, this little number could be SERIOUS.