The Scottish Business Insider reports the owner of Powerwall, after many years of testing, has developed lightweight steel frame and walls for building modular homes he intends to market internationally.  Taking a page from the mass production of automobiles, Dominic Tedesco says building has changed little since the Roman days, and his structural steel components lock together similar to Legos.  The honey-combed steel walls are made in his native Italy, and agreements have been signed for production facilities in Saudi Arabia and Qatar.  In addition to combining other technologies for energy efficiency, one goal is to wire homes with sensors to detect emergencies, especially useful in homes for elderly and disabled persons.