While searching for a blue mini-dress I could use to make a Star Trek: TOS science officer uniform (because the costume versions apparently do not come in a size above "Medium" at any stores), I have come across a veritable treasure trove of dresses you could use for a "slutty Elsa" costume. You know, if you wanted a slutty Elsa costume. Because that would totally be in character and all.
ETA: I guess I wasn't as clear as I thought. This was a commentary on how Disney character costumes seem to boil down to short, low-cut dresses when it comes to Halloween costumes for adult women. Of course there are more egregious examples of "slutty" or "sexy" versions of costumes — none of these are intended as Elsa costumes. I just felt they looked very similar to costume company renditions of other Disney princesses. And yes, Elsa's actual dress does have some "sexy" elements to it, but it's very different from how companies tend to translate Disney princesses into "sexy" costumes.