Offical release date leaked
We will be getting it on Dec.6/live on the 7th.
"That's why he's having a special sale for his Vicious' Hammers for one week only from December 1st through the 6th, 2010.
Hammer your favorite item and add a slot! You'll need the best equipment for when the Black Mage shakes up Maple World!"
http://maplestory.nexon.net/News/Events.aspx?boardNo=201&contentNo=00AJD&pageIndex=1
EDIT: I just noticed same day as Cataclysm </3
December 2, 2010