Well, I'd say Dean didn't win the fight in this ep because he was A: more interested in killing Ruby and B: still doesn't really want to hurt Sam, whereas Sam, at least in some ways, wanted to fuck Dean up.

I love the theory that it's all one big fake out. That would make my season. And I could see the boys doing it--I think they'd still know each other enough to be able to pull it off, the reveal could show us a quick flashback of looks or specific words chosen or something, I don't know. Doubtful it will happen (what with the whole demon blood angle), but it would be beyond cool.