I made a small discovery. So naturally I decided to write a long post with lots of pictures, just to show this small discovery.
One of the Xbox 360 near-final debug builds of Rayman Legends contains a file called "masterTFI.bin", listing various properties of a lot of the textures in the game (compression mode, filtering, etc.). This information is normally stored in the texture files themselves, so this file isn't used in the final game.
Looking closer at this file, I found out that it references some texture paths not included in any build of the game! This means it was likely generated based on the source assets of the game. Because of this it includes texture paths in the developers' "personal" folders, but also some much more interesting paths...
For example: multiple textures for "faery" (which is what the nymphs were named internally in Origins).
Or, textures for paintings that never made it into the game, that I found sound files for before: "Drak's Nightmare" (Dracula world) and "Crouching Huns" (the Huns world).
But the most interesting part of this, to me, is that there is another painting that I did not know about, with the internal name "simbad"
The list also references textures for this world, spelled as "sinbad" in the world_old folder. I guess the inspiration for this world was the movie "Sinbad: Legend of the Seven Seas" then?
Also interestingly, this sinbad world apparently included the enemy "pink monkey", for which I found unused behavior years ago. This AI still exists in the game, but without animations and textures, there's nothing we can really do with it. Here's a screenshot from a class for it in ubi-canvas. And don't ask me what it is... I'm as clueless as you are.
It would be fun if we could find out more or see screenshots of this Sinbad world, but alas it seems nothing remains of it aside from these paths.
Finally, this sheds a bit more light on the old world order of the game:
Even in the final game we have a "world_old" directory containing some things, but not that much. It seems that:
- World 1 would have been the medieval world. This would contain 3 main types of environment: the castle, the swamp, and the enchanted forest (I thought this was a separate world before but I guess it was all medieval). Note that the swamp texture names include "mushroomlight" and "mushroomsafezone". This is actually the environment we saw in the earliest trailer, where Rayman runs from the Dark Creatures (if you ever wondered why you scare those Dark Creatures with firework mushrooms growing in the middle of a volcano, it's because they were originally made for this place instead).
- World 2 would have been Olympus Globus (and Hades), which is just Olympus Maximus now.
- World 3 and 4, we know nothing about. Perhaps Crouching Huns and Drak's Nightmare were here?
- World 5: this newly discovered Sinbad world. Considering Sinbad was a sailor, I'm guessing this was partly a water world. The texture names here support this, with "spikyfish" and "abyssalhands" being straight from the Origins water world.
- World 6: A jungle. But this one is different from the forests in World 1, as it seems instead of light foresty places, this would have been a deep jungle environment. Some textures in this folder remain in the final version, but most were moved. All of those textures have this very overgrown look. Most notably, the textures for the Teensy village in the intro cinematic were once all in this folder. I thought this was kinda weird because it didn't fit the medieval theme at all, and now it seems likely that it was once in a different world entirely.
- World 7 was the Land of the Livid Dead, including both the Land itself, as well as a "jail" that became the castle environment in the medieval world.
For me personally, this clears up a thought I had about some worlds in the game. Fiesta de los Muertos and 20 000 Lums Under The Sea don't fit the "legend" theme of the game. Perhaps these worlds weren't planned at first?
Thanks for sharing, it's much appreciated as always
Well, it's good to know that they can be tied together a bit more neatly than the final game would suggest! 
Then I guess the 20000 Lums one speaks to modern "legends" of spies, but that's definitely stretching it quite a bit!
Wind 
