A port of Fate/Hollow Ataraxia is in the works for the Vita according to Dengeki PlayStation.
This entry in the series takes place after Fate/Stay Night which was re-released on the Vita towards the end of 2012. Following Bazett and Avenger on their journey to emerge victorious in the 5th Holy Grail War, the Vita version will include full voice acting. At the minute, this has only been rumoured for a Japanese release with no news on any Western translation.
The game, developed by Type-Moon and originally released on the PC back in 2005, has no confirmed release date as of yet. For further news regarding this, be sure to check The Vita Lounge for updates.