Ubisoft Massive, the publisher's Swedish studio which created Ground Control and worked on Assassin's Creed Revelations and Far Cry 3's cooperative mode, is working on an "AAA Next-Gen Online RPG", according to the LinkedIn profile of game designer Mark Cartwright.
Massive is also currently advertising for a number of roles within the studio, including an "experienced Lead Level Designer to join an international team working on a AAA Online RPG." This listing also adds that "in this position you will lead a Level Design team in building the best gameplay experiences ever conceived. For any game. Ever". A bold promise.
What's not clear is if the new game is based on an existing IP or if the title is an entirely new creation.