In this design, the complex and expensive stuff, like kitchens and bathrooms, and the small stuff, like bedrooms and closets, are done in the factory in fairly traditional modules. This is where the factory shines, and the value of the box is fairly high because all of the expensive stuff is here.
then, when these two boxes are brought to the site, a roof is installed on site from prefabricated trusses, and two end walls are put on. There is more site work required than a normal prefab, but it's not complex work and it only requires a few trades.
The Breezehouse takes advantages of the virtues of modular construction and leaves its biggest problem, the cost of shipping air, behind.
You can see it this weekend at the ::Sunset Celebration Festival, south of San Francisco. by [LA]
Conflict of Interest declaration: This author is in the modernist prefab business and hopes to sell the Breezehouse as well.