O_o"" I've not a clue why you're all so sure it'll be Stunky. She hated the thing when they ran into with officer Jenny... heh, I just don't think it'll happen.
I think she may get either a pink or blue Shellos, and Dawn will get the one that she doesn't have. The anime has turned into sort of a mirror of the main characters pokemon, and Team Rocket gets the opposite. (May-Beautifly; Jessie-Dustox) (then the Meowth and Pikachu, cat and mouse, thing...)
So, my pick is Shellos or Gastrodon, it could be cool in contests and it's strong and cute~ <3