As much as I would want this to be real, I'm really doubting the existence of this. It sounds more like a dream and a rumor than an actual world. I'm pretty sure we have basically seen everything in Mario 64 including the betas of it too. If you and what multiple people saw was real, there would've been very limited copies and it would've been talked about more back then. Also if you were you check the coding or try hacking the game, you have to do it with your copy that it happened on since there were multiple patches and fixes throughout different versions of the game.