I caught a show on Netfix about unusual houses that showed them.

Interesting series. There was a fair amount of over the top, what the fuck, but it also included some off the grid, sustainable and green living arrangements. One guy designed his house around uncut 4 X 8 foam core panels. It eliminated a lot of cutting and fitting. Although it took him two years to design it, the house was built in two weeks and cost, if I remember correctly, $40,000, including utility work.