Does the future of retail have four tires and a trailer hitch? Joel and Lucia Kamm, husband-and-wife founders of the Woburn startup Flexetail, are betting it does. The company’s trio of retail trailers have recently been busy, selling Bruins gear outside TD Garden, canned iced coffee outside Copley Place Mall, and Gillette’s new heated razor on the Greenway. But it’s a business with plenty of challenges, from navigating municipal permitting and regulations to the labor costs of hauling a trailer from place to place for different events. Read more at Boston Globe.