Sept. 11, 1961 - Hollywood producer Samuel Bronston (lower left) is convinced that the salvation of the film industry lies in expensive, three-hour, reserved-seat, costume spectacles, and he has acquired the production capital to demonstrate his point. In New York today to prepare for the release of both "King of Kings" and "El Cid," he outlined plans for three similar "large-scale productions." They will deal with the Boxer rebellion in China, the French Revolution, and the fall of the Roman Empire. All three widescreen color films will be made in Spain with budgets of around $6 million. "The Fall of the Roman Empire" will be first on the agenda, with February as the starting date for Anthony Mann and probably Charlton Heston, the director and star, respectively, of "El Cid."