It's unofficial as hell, and Nintendo are probably in the process of nuking it from space, but for now you can totally download this Legend Of Zelda maker and start making your own version of a Zelda game. Hurray!
We covered this in September, when the project was in its infancy, but now it's been developed further and is available in Alpha form.
It doesn't look all that flexible, and looks a little bit like RPG Maker or some other user friendly tools, but it might be fun to mess around with.
But it most likely won't be long for this world.
It begs the question: would Nintendo ever make a Zelda maker? Would it be worthwhile? My guess is no and... maybe?
No, Nintendo probably wouldn't release a 'Zelda Maker', probably because it would be way more complicated than Mario Maker and almost impossible to make user friendly. Maybe because well, I'd love to play well designed user-created dungeons.
Just make it Nintendo! Make it happen.