Jon joined Sugarland on October 18, 2010 in New York City for the American Express Unstaged event. With a bit of luck, "Who Says You Can't Go Home" will be uploaded to the Amex YouTube channel (Some of the other Sugarland songs are up). For now, the best I can do is this 1:48 snippet with dodgy sound:
Hath has, however, posted a cool picspam of the performance on her blog.