343 Industries is actively seeking staff for a next generation Halo title.
A job listing on Microsoft's career website dug up by VideoGamer explains that the studio is looking to hire an experienced graphics designer ‘to help create the current and next generation of game visuals in the Halo universe.'
The listing also mentioned DirectX 11 experience being a plus, which has been widely rumoured to be the graphical framework for Microsoft's next-generation console.
No official confirmation on anything of course. On the record 343 Industries is currently readying Halo 4 for its November 6th launch.