Nothing widens the eyes of a film producer like a pitch with a superhero angle. And with so much talent emulating Disney, Universal and Paramount in striking cross-platform deals with Broadway in mind, here's mine: Move The Fortress Of Solitude, the best new musical of the season, to 42nd Street. Then shoot it. With a name like Fortress Of Solitude, you don't even have to build the brand. Just billboard a giant arrow pointing from the Public Theater to Times Square and…