"Why not just use google maps, or Zillow to locate areas with large estates and find a house with a ten car garage."
That works too except that it won't reveal exactly what is in the home.
You see, I have known three different people who had their entire home audio systems stolen, and I have heard of many more over the years. The funniest theft I know of happened during a party when everybody got quite wasted out in the back yard, and the thief just waltzed out with the living room system.
My home insurer strongly suggested I insure my system against fire and theft. Call me paranoid.