I read this book in my dad's collection at least ten years ago. I feel like the title had something to do with time, but I could be wrong. The cover has a brown bald head (you just see the back) approaching three young adults in what looks like a spaceship.
In the book, the main character is Caucasian and living in America, but then his dog does things it isn't supposed to do (like climb trees) and he realizes he's not in the time and place he thought he was. He meets a couple of other race-preserved people who were being raised as if in other times and places (I think there was a Chinese girl named Meilin? Or Mei-lan?).
They try to find a way back home from this planet populated by people who all have the same color skin and hair, they call each other either "Stan" for standard or "Norm" for normal, I can't remember which. There's also something about their houses being clear and shifting or adjusting according the what the inhabitants need...