Saw some activity here in Louisville today - not sure if it's for Sprint. They've been working here all week at 908 Main st in Louisville.
Here are some pictures:
http://i.imgur.com/va64MAo.jpg
http://i.imgur.com/G86iEDg.jpg
http://i.imgur.com/YCEvura.jpg
http://i.imgur.com/3XcR5Js.jpg