This might be the most eccentric country retreat ever, but it really stuck in my mind. The owners are camping gear designers, and the two yellow domes are (fairly) ordinary camping tents.

The parts of this house that require plumbing -- kitchen and bathroom -- are permanent and "indoors". Everything else is outdoors and/or fungible.

There's electricity, hot water, and a kitchen -- not to mention iPads, Internet, and a clawfoot tub!

It's almost like indoor living!! :)

This is another variation on the same basic idea. The kitchen and bathroom are inside a permanent (although lightly built by modern standards) structure, but the rest of the "house" consists of tents and decks. And actually there's a big outdoor kitchen and outdoor shower, so in principle almost every function could be done without permanent walls.

http://www.sunset.com/home/idea-houses/summer-retreat-home-celebration-weekend-2007-00400000014754/