Have you ever heard of glamping? I hadn't, until I stumbled across Canopy and Stars, a British site that hooks you up with gorgeous places to stay in the wild -- glamping means "glamourous camping." I love the idea of staying someplace rustic but also luxurious. Yurts seem to be big in the British Isles.
This is in Alicante.
This is in the Dordogne, France. Those are the bottoms of glass bottles in the walls.
You can stay in one of three gypsy caravans at this spot in Scotland.
This hobbit house is in Cornwall.
If you're not feeling the hobbit thing, how about an Iron-Age roundhouse in Cornwall?
This treehouse is near Bordeaux, France.