Chocolate Brown Dresses/Black Tuxes

My theme colors for my wedding are light "icy" blue with chocolate brown (more brown with blue accents). I really want the girls to wear dark brown dresses, and I haven`t figured out what to do about the guys. I really want them to wear black tuxes, but I`m having such a hard time trying to imagine what the brown with black will look like. Does anyone have any suggestions about what color vest they should wear? I would LOVE to see pictures of weddings where this was done, or at least something similar to this. If anyone has any advice or pictures to offer, I would really appreciate it! Thanks!