Yes, once. It's a sensation that is...odd. Hard to forget.
It was about three years ago, so I was...11. The dream, I forget what it was about. I think I was in the jungle or something. It was a first person dream, a rarity among the few dreams I can remember. So, I was standing there, and suddenly my perspective pans out. Steadily.
So now I can see the back half of myself. Third-person perspective, so to speak. I move my arms, examining them, wondering whats going on. Mainly because as I move them, I'm seeing this from behind. I turn around, staring down my current perspective, which is a few feet behind me at this point. And it just hits me...
"Oh shit. I'm dreaming this."
I walk towards it a bit, moving my arms as if I was looking in a mirror. It only lasts a few seconds, however, because I woke up right after that.
So yeah, they're perspective warping....Weird.