I have seen a lot of snowboard and ski films and two snowboard films i have seen prove this. One is called Red Bull Project X, all about his private half-pipe, the exclusivity of it, how it was built, and what tricks he literally created on it. So the thing about the private half pipe is all too true.
A documentary about Shaun came out a few years ago called Dont Look Down, showing a day in the life of Shaun White. He says himself after placing SECOND in X-Games slopestyle, how disappointed he was and that he felt like nobody could beat him. He then went on to say that when he rode pipe in the Olympics that he felt like he was unstoppable and there was no way he would lose (for those of you who don't know, he did take first at Olympic snowboarding superpipe that year).
So to confirm the theories, I would say its all too true that Shaun White is self-centered, over-competitive, and will do anything it takes to win.