I guess part of the huge price tag is the location. But the notion of Steampunk as residential "high fashion" is interesting.
I used to participate in a family business whose main purpose was to sell 17th C. - 19th C. European / Spanish inspired "residential fantasies" as I call them (i.e. custom carved architectural facades, fireplaces, fountains, balusters -all in natural limestone) for multimillion dollar homes. It was "architectural high fashion," as it were. Did well for a while, but the business went south in the mid 2000's when every low level wealthy person suddenly felt an urge to live an Tuscan grainery / farm house. Every thing was Tuscan this -Tuscan that.... Tuscan food, even barfy romance Movies situated in Tuscany??
If you were not selling brown sandstone rocks by the ton you were not in business.
Maybe I can revive the business building Steampunk mansions!