This is one of my favourite mansions I've ever built. I used concepts found in a famous home in Toronto here: Integral House

 I really designed the house to be large feeling without losing the homeyness that you get in smaller open concepts. The design is to have two guest bedrooms in the main house in addition to a large main bedroom with on suite.  

To me that wasn't enough, so I made sure to include a sizable guest house. 

The underground garage is designed to take at least five full sized sedans with comfortable breathing room.