Admit it: You've sung along to ''More Than a Feeling'' at least once in your life. So has Charlotte, N.C.'s Tommy DeCarlo and this summer, the Home Depot staffer is one-upping all the world's amateur karaoke champs by actually joining Boston on their North American tour, filling in for late frontman Brad Delp. DeCarlo scored this dream gig after Boston guitarist-founder Tom Scholz came across his MySpace page, where he'd posted some spot-on Boston covers. So what's next after the tour? DeCarlo says he plans to return to his Home Depot job. Now that's loyalty.