Halloween // costume help for pear-shaped body type

I could really use some help with a costume idea. I have a pear-shaped body - I'm small up top, bigger at the waist, and bigger than that at the hips. It's very, very difficult to find even normal clothes that fit right and are flattering - trying to find a Halloween costume seems impossible.

I was hoping to do something like a pirate or a Jedi, but both of those (typically?) have belts exactly where it is NOT flattering on my body. I also need a costume that comes with pants, not a dress, because this needs to be something I can wear to work.

Does anyone have any ideas about costumes?