In a recent spate of information from Tetsuya Nomura, he has revealed that the voice cast for Final Fantasy Versus XIII is currently being selected, for the Japanese version at least.
When touching upon the development progress for Versus he stated:
"Agito and Versus have different production styles and progress states, but they're both presently undergoing voice casting."At least some kind of progress is being made on the title, as opposed to it being stuck in limbo even more. It's also interesting that he seems to state that Agito is next in line, before Versus XIII.