If something were to spark an actual relationship between Ash and Dawn, what do you think it could be? What kind of scenario could you see unfolding to lead to it?
Like lightandwill said, so many ideas could happen in the anime and its all down to the writer to decide but to me I think they would perhaps have secret crushes on one another but do well to hide it. Maybe later on of them spills to beans to someone and the other one knows. Then it starts to get awkward but eventually admit their feelings to each other.