Shigeru Miyamoto's been harping on about a multiplayer Mario for ages, but in a recent interview with Wired.com he revealed there was planned to be two-player support for Super Mario 64, but that it was scrapped.
Miyamoto: With Mario 64, we had an experiment that took advantage of the idea of the screen growing larger and smaller depending on how far apart the characters were. So we had Mario and Luigi running around in that 3-D world, but we ended up not using it.
Wired.com: Why did you decide not to use that Nintendo 64 game with Mario and Luigi?
Miyamoto: Ultimately, it’s the idea of processing speed and working within the constraints of the hardware. The DS Mario 64 had a mode with something similar to that, where you were playing with four characters.
And to think, a thousand playground arguments and fake cheats stemmed out of Mr Miyamoto's decision to scrap Luigi. How heartless can one man be?