As to my current knowledge, Michigan has the most known XL's, (8) and counting.
1.- Bad Axe, MI (Comcast)
2.- Coldwater, MI (Charter), (I found that one today!)
3.- Houghton Lake, MI (Charter)
4.- Gaylord, MI (Charter)
5.- Petoskey, MI (Charter)
6.- Sault Ste. Marie, MI (Charter)
7.- St. Ignace, MI (Charter)
8.- Traverse City, MI (Charter)
In second place with 6, Pennsylvania.
1.- Bedford, PA
2.- DuBois/Punxatawney, PA (Comcast)
3.- Edinboro, PA (Coaxial Cable TV Corporation)
4.- Fawn Grove, PA (Armstrong)
5.- Sharon, PA (Time Warner Cable)
6.- Warren, PA (Atlantic Broadband)