Supermodel Marisa Miller has signed on with Harley-Davidson to be the face and body of their new V-Rod motorcycle."My uncle rides Harley's," said Miller, who is a Victoria's Secret model and was on the cover of this years Sports Illustrated Swimsuit Edition."My dad rides bikes, and it's such a cool thing to have something I've grown up around."The average age of Harley buyers is 47, according to