Engineer Drew James from Ubisoft Reflections posted a picture with Prince of Persia's various incarnations through the gaming ages, with the fifth slot reserved with a teasing question mark.
He asked what was next for the series, but his twitter feed has since disappeared. Other twitter accounts were copied in, including Jade Raymond. Ubisoft is leaking serious sand.
Already there are rumblings a new Prince of Persia is in the works using the UbiArt engine which powered the fantastic return of Rayman. It will be 2D but made to look 3D.
Also the Prince's body will have each limb animated independently,the source, much like Rayman himself in many ways. Ubisoft is also using the UbiArt engine for the soon-to-release RPG Child of Light. The last major Prince of Persia was The Forgotten Sands back in May 2010.