Possible Clues:

• "Mrs. Miniver" studio
• 45-Across rival
• Las Vegas's ___ Grand
• Big inits. in Las Vegas
• ''When the Lion Roars'' subject
• Studio with a roaring lion
• 'Grand' letters
• 'Ben-Hur' studio of 1925 and 1959
• ''Spectre'' studio
• 'More stars than there are in heaven' company