A young family who lives in a yurt – in Alaska. Nice slideshow included.
This one has a diameter of 24 ft. = 452 square feet. They say it cost $14k, and took them 3 days to set it up.
When we toured the Oregon coast a few years ago, we stayed in some smaller ones (16 ft. dia.) operated by the state parks system – they were all sturdy, and surprisingly comfortable.