Arc System Works announced that Guilty Gear XX Acent Core Plus R will be coming to Vita in the west. They just haven't said when this will happen though.
The publisher promised on the Blazblue Facebook page that the game is going to work just as well as Blazblue does on the Vita. Currently its unknown if it will be a retail game or just digitally just as it was released on PS3 late last year.
The rating for Guilty Gear XX Accent Core Plus R has been filed for a rating in Germany strangely enough so hopefully other regions will follow suit. The arcade version released in Japan last fall. Check out the trailer bellow.