What about containers clad in adobe or papercrete as far as additional insulation and aesthetics?
I like the courtyard idea as well. With a good membrane ... the roof could be a planted green roof.
Minimalist Adobe Brick Home is a Box Within a Box
A box within a box, this simple house composed of mud bricks formed into a contemporary structure is an elegant synthesis of old and new. Built in Marfa, Texas, a town better known for the artist Donald Judd’s boxes than its dwellings, the Mud House stands out as a Zen-like oasis. Oakland-based Rael San Fratello Architecture designed the home with simplicity in mind to keep costs low while maintaining a high level of energy efficiency. Read on to learn how they did it.
For the lower portion, dense bricks that can withstand water and weight were brought in from New Mexico. The lighter colored bricks set above the concrete lintels weigh less and were sourced just across the border in Mexico. The lintels subtly break the monolithic, locally-sourced, mud plastered walls.
The style is also minimalist on the inside. The kitchen and bathroom extend from an interior box that houses the plumbing, boiler and storage, so as not to complicate the adobe wall construction. A radiant heating concrete floor and fireplace keeps the home cozy in the winter, and a walled-in courtyard provides complete serenity.