I just remembered that Chicken Wiggle for 3DS has a whole bunch of user-created levels, and I'm not 100% confident anyone else would have preserved them yet given that it's an obscure game.
Chances are the game probably relies on the developers' own servers instead of Nintendo's since there's a game-specific online ID, but I also wouldn't assume those are going to be around forever either.
I guess if I want to help with this I'll have to attempt to reverse engineer how levels are downloaded, and packet sniffing stuff is not something I have any experience with.
