For years, In-N-Out Burger fans have watched the massive structure rise above the Las Vegas Strip. Now, the wait is over. The California burger giant has officially opened its long-awaited BLVD location, an 8,000-square-foot showcase that instantly becomes the second-largest restaurant in the company's portfolio and its most ambitious Vegas project to date. According to SF Gate , the new restaurant opened on Tuesday, June 9, on the top floor of the BLVD shopping and entertainment complex next to the MGM Grand. With room for 170 diners inside and another 50 on a rooftop-style terrace overlooking the Strip, the location dwarfs most traditional In-N-Out restaurants. It also includes a dedicated company store packed with merchandise, making the site part restaurant, part tourist attraction. In-N-Out has spent much of the past year explaining why it isn't expanding in other directions.…