I'm not sure how much Shag dancing you'll find outside of North and South Carolina. Charlie Womble and Jackie McGee hold an annual event in May in Atlanta. It features both WCS and Carolina Shag: http://www.usagrandnationals.com/
My next door neighbor back in the day, Betty, came from South Carolina, and she and her husband Stanley were old-school shag dancers. Stanley was also a song-and-dance man in vaudeville when he was young, and boy, could he dance. I wish they both were still alive; would love to have learned to shag from them.