I've often wondered how many of these homes in CA that burn would be saved by a cistern, a gas water pump, Hardiplank or stucco walls and tiles or steel on the roof?
A temperature-actuated, or remotely-controlled sprinkler system would be another option.
The way things are going these days, a couple of 40 foot high cube containers built into a hillside looks better all the time: temperate, secureable, low visibility, and very unlikely not to survive wildfires.
And best of all, cheap.