Recently I heard the term "monster mansion" used on local radio to describe inappropriately-huge structures that purport to be single-family homes in the hillsides. I was very glad to hear it, because we at Committee for Green Foothills came up with the term several years ago. Others may have thought of it as well, but we've used it as a term that accurately distinguishes those buildings from single family residences. Above some size, a structure (or more usually, a complex of structures) is not the single family residence that's zoned in the hillside. Given the direct habitat destruction and indirect impacts from constant stream of staff servicing these structures on a permanent basis, monster mansions cause significant problems in the hillsides and should be limited to a maximum size.
So we're glad that the term is starting to come into common use.