In-N-Out Burger is about to make one of its boldest physical statements yet, with a massive, multistory location on the Las Vegas Strip nearing completion after more than a year of construction. SFGate got a first-hand look at the gigantic construction on Friday, April 24. Set inside the BLVD retail complex next to the MGM Grand, the upcoming restaurant is expected to open later this summer and is already drawing attention for its size, visibility, and prime location on one of the world's busiest stretches. The nearly finished site spans about 8,000 square feet and includes a 2,500-square-foot outdoor terrace overlooking the Strip, a large indoor dining area, and a dedicated retail space for branded merchandise. Despite its scale, the location will not include a drive-thru—an intentional design choice that reflects the pedestrian-heavy nature of the Strip.…