If this isn't the largest single family dwelling in the state of Indiana, then it's gotta be right up there. Steve Hilbert, the founder of Conseco, moved out of this Carmel, IN mansion in January 2005. The property contains 55,000 square feet of buildings, including the 23,000-square-foot mansion. House contains a replica of the Indiana Hoosiers basketball court. Go Hoosiers!
http://www2.indystar.com/library/factfiles/people/h/hilbert_stephen/hilbert.html
http://homesoftherich.net/2008/08/le-chateau-renaissance-stephen-hilberts-mega-mansion.html
http://www.luxist.com/2006/04/27/le-chateau-renaissance-estate-of-the-day/