In Emulators / NES ROMs

Is there maybe a "Super Mario Bros." hack where you can play with two players simultaneously (like in "Rush n Attack" or "A Nightmare on Elm Street")?

I've never seen one, but I bet that'd be tricky to pull off. That's doing more than your average changing of tiles and editing words or levels. You could try searching various search engines, but I would think that a hack such as that hasn't been made. If you happen to find one though, let us know