Here is a concept that some vacation-bound or retreat-seeking individuals may love. It is called the Isolee, an off-grid solar powered retreat concept.
The self-sustaining building was designed by Tjep, something which reportedly opens like a standard cupboard. Among the features of the Isolee include a roof-mounted solar tree which rotates to collect solar energy which should be enough to provide the necessary power requirements when you got out on retreat.
Though a concept the Isolee seems like a cheeky way to get away from it all, especially for the folks who sorely need a break in an eco-friendly kind of way.