Revenues have been sizzling all summer for businesses that give residents and visitors to Greater Reno-Tahoe an escape from sweltering 100-degree heat.Andrew Laughlin, owner of Sand Harbor Rentals, says revenues are up about 15 percent on a daily basis from 2011 for rentals of kayaks, personal watercraft and stand-up paddleboards at one of Lake Tahoe's most popular beaches. Laughlin says a rise in visitors to the Lake Tahoe Basin this summer, coupled with the growing popularity of paddleboarding, has Sand Harbor Rentals eyeing a record summer."Kayaks will always be popular at Lake Tahoe, but paddleboarding is the new hot item …