Could a hypothetical "World's Finest" movie have worked between them? I say this because both Keaton and Reeve are in the 1994 movie called Speechless. I just watched a portion of it on HBO Family the other day and I it was a huge geek/mark out moment when I actually saw "Bruce Wayne and Clark Kent" in the same scene together. I believe this was the first time that an actor who played Superman appeared in a movie/TV show (not counting stuff like Super Friends) with an actor who played Batman. More recently, Dean Cain (Superman on the Lois & Clark TV series) appeared in a movie called 5 Days of War with Val Kilmer (Batman in Batman Forever).
The one problem is that you have to get a good reason or excuse for Clark Kent to be in the same universe as Bruce Wayne (and I'm not talking about George Clooney's infamous Superman name-drop at the start of Batman & Robin) without it feeling very contrived or forced. I can see Clark Kent working as a reporter for the Gotham Gazette with Vicki Vale and Alexander Knox. Meanwhile, Max Shreck from Batman Returns and Ross Webster from Superman III are pretty similar characters. Both Shreck and Webster are conniving, megalomaniacal business tycoons. Another way to look at things, is that when General Zod, Non and Ursa are on a worldwide rampage during Superman II, Batman can over his services if they ever get into his jurisdiction of Gotham (such like when they invaded "East Houston").
The one problem is that you have to get a good reason or excuse for Clark Kent to be in the same universe as Bruce Wayne (and I'm not talking about George Clooney's infamous Superman name-drop at the start of Batman & Robin) without it feeling very contrived or forced. I can see Clark Kent working as a reporter for the Gotham Gazette with Vicki Vale and Alexander Knox. Meanwhile, Max Shreck from Batman Returns and Ross Webster from Superman III are pretty similar characters. Both Shreck and Webster are conniving, megalomaniacal business tycoons. Another way to look at things, is that when General Zod, Non and Ursa are on a worldwide rampage during Superman II, Batman can over his services if they ever get into his jurisdiction of Gotham (such like when they invaded "East Houston").