From the experts:
This familiar but never popular Welsh surname name might be a good Sean alternative-- and we're starting to hear some berrybuzz about it. Vaughn is an alternate spelling.
There have been three major musical bearers of the name: British classical composer Ralph Vaughan Williams, 1940's U.S. band leader and singer Vaughn Monroe and the great jazz vocalist Sarah Vaughan. And two more current surnamed Vaughans: comic actor Vince and musician Stevie Ray.