After the 1996 release of Super Mario 64, magazines for years mentioned Super Mario 128 that would feature both Mario & Luigi for release on the N64 or its 64DD add-on. In an interview with Level3 Magazine in Sweden Mario creator Shigeru Miyamoto mentions the game as one of his lost projects. Here’s the quote:
“Super Mario 128 was just one of many experimental games we had. Suddenly, everybody started talking about it. I’m in the all-too easy habit of starting a project only to later on not do much of it. There is a great deal of unfinished work on my desk. I worked on a prototype for the Nintendo 64 game with Mario and Luigi in it for some time.”
Back in 2000 Nintendo showed a “Super Mario 128 tech demo” that, while simply featuring 128 Mario’s to show the GameCube’s power, had everyone guessing as to whether or not a Mario & Luigi 3D adventure would appear on GameCube. Well, a few years later Super Mario Sunshine appeared without Luigi and this is confirmation the idea simply got dumped in Mr. Miyamoto’s drawer.