It would be great if there was some sort of experiment or study done to see if there was in fact dominance, but I am certainly not going to house my snakes together just to find out.
I am going to guess most people who have enough snakes to do this type of experiment wouldn't want to.
Just a few days ago there was a thread where someone was keeping two hatchlings together. One was eating perfectly fine, but the other had not taken a meal. He separated them and within 2 days the non-eater started eating again. To me this points to "dominance".
As for breeding, yes the smaller males can breed the larger female.