I always wanted to live in either a tree house or a hobbit house.
They've built hobbit houses, now, in New Zealand, where you can try them and see if they're for you. According to the LA Times:
Who knows how J.R.R. Tolkien would have designed a motel but the Hobbit Motel in New Zealand seems to have real fantasy appeal.The strange little building with porthole-style windows is built into the side of a hill in Waitomo, a region on the North Island known for its caves and waterfalls. (Woodlyn Park)