The above image is a screenshot of Spanish website Xtralife, who have just listed Majora's Mask 3D for sale--24 hours before a 3DS Nintendo Direct. There's the possibility that they're just speculating, but remember that leaks have occurred this way before--remember Donkey Kong Country Returns 3D? We could very well be seeing an official announcement tomorrow. If you click the image, the index just reloads; this could mean that while MM3D is in their system, the page isn't yet live. Suddenly, tomorrow's Nintendo Direct got a lot more interesting.
UPDATE: Thanks to some help from a Brazilian fansite, more details about the listing have come to light. Two very interesting details; the first is that the page was registered well before the page for Pokemon X and Y--this could mean retailers have known about MM3D for a while. The page was supposed to stay private, so who knows why it slipped out now; maybe it was supposed to go up this time tomorrow instead. Secondly, we have a potential release date; November 8th. A lot of Zelda games are released around that time, including the upcoming Windwaker HD; could we see both of these at once?
Also, adding credibility to Xtralife, they were the ones who revealed the 32GB Nexus 7 three weeks before it was announced.