The Dunsmier house is actually called Craigdarroch Castle.
It is the classic story of, Guy starts poor, Guys gets rich, Guy builds BIG Expensive house, Guy dies before house is finished, Guys' wife hates house but can't afford to move and only lives in it for 9years.

You can find more info at; www.thecastle.ca


As an aside, the son of the guy who built the Castle also built a large Castle like home which is called Hatley Castle and was used for the school during the filming of X-Men.