Hm... that's an interesting thought, isn't it? A Buddhist Saudi Arabia... Could such a thing be possible? Buddhism has got to be a solid contender for the most peaceful religion on Earth (unless you count us atheists, of course). Lets see... nations that are expressly Buddhist... there's Thailand, Cambodia, and Bhutan. Those are the only three countries where Buddhism is the state religion. Of those, I think the closest comparison to what a free Tibet might look like would be Bhutan. The only thing that I've ever known about Bhutan is that they measure Gross National Happiness, as opposed to Gross Domestic Product. That seems like a plus to me. Maybe they've got their priorities straighter than we do.
Or, maybe not... Wikipedia says that in the 80s and 90s the (Buddhist) Bhutanese monarchy kicked out a fifth of the nation's population in order to preserve its national culture and identity - maybe that fifth just weren't happy there. Of course, Bhutan isn't beheading people for shoplifting or practicing witchcraft, and they don't have religious police that will imprison people for such crimes as driving while female. At worst, a free Tibet might show the door to the Uyghers (Central Asian Muslims), and to the Han Chinese and to the Hindus, but I doubt they'd even be able to do that much. Tibet would be a big country with a very small population and very harsh terrain. Any Tibetan state would have a hard time kicking out any group, even if they wanted to.
You may say I'm a dreamer, but I'm not the only one
I hope someday you'll join us, and the world will be as one