Billionaires are developing multi-million buck homes on mega-ranches. Sales agent Robb Nelson says it is an real estate “Bonanza.” Outdated Original York City Mayor Michael Bloomberg paid $46 million for a 4,600-acre ranch in Colorado. A 41,000-acre ranch in South Dakota is going for $37 million. It entails 5 bedrooms, a fully geared up fitness heart and a home theater. The ranch is also a money maker with crops, over 2,000 cattle and hundreds of untamed mustangs.