From Unseen64
Once upon a time, Rayman 4 was in the works, but was mysteriously canceled, and abruptly into Raving Rabbids. While we have no idea how good Rayman 4 may have actually been, based on this report from Unseen64, it sounds a hell of a lot cooler than anything Rabbids had put out.
Unseen64 notes that the premise involves Rayman starting off in a video game training camp, and that eventually, you’ll realize that every character knows they are in a game. The only antagonist would have been a rendition of Dark Rayman, who represents glitches and bugs within the game. It apparently was intended as a reboot of sorts with a brand new tone on GameCube, PC, PS2, and Xbox.
Based on this info, I really dig this concept, but alas, we’ll likely never see it.