Many moons ago, Free Radical were bought up by Crytek and despite a few promises during the interim concerning the completion of Timesplitters 4...nothing has really happened other than rumour and counter rumour.
The cause has not been lost though, as discussions do continue as can be seen via Cevat Yerli, CEO of Crytek and designer manager for Farcry explanation of the situation in an interview on CVG (http://www.computerandvideogames.com/353240/crytek-ceo-weighs-options-for-timesplitters-4/?cid=OTC-RSS&attr=CVG-General-RSS) recently.
This led to a campaign started on Reddit to supply him with the numbers he needs to get this rolling: Reddit petition (http://www.reddit.com/r/gaming/comments/uy7h2/crytek_thinks_there_isnt_enough_community_support//) that one did well, but the range of contact methods proved a bit scattershot.
As a result he has asked for comments and re-tweets via his Twitter account here (https://twitter.com/#!/RealtimeCevat) so that Crytek can evaluate the demand.
This is more for the fans of the game series who might not be aware of the current situation and wouldn't mind seeing it back out there again.