Ubisoft's Marc Parenteau talked briefly about Assassin's Creed at a joint press conference with Nintendo today. While he couldn't confirm if the title would be a new title made exclusively for the Wii U, or a port, he did note that the current engine translates very well to Nintendo's new platform.
Speaking about the unique Wii U controller, Parenteau noted that there were "many possibilities" for the additional screen, including a persistent on-screen map, the ability to switch weapons using touch, an interactive database, and puzzles specific to the touch screen. Even Eagle Vision may be placed on the second screen.
These were entirely hypothetical, of course, but it shows the kind of approach Ubisoft is taking with bringing its hit franchise to Nintendo's new console.