Final Fantasy Versus XIII was first made public in 2006. Square Enix has shown screenshots and trailers. And now, Versus XIII's designer is happy to report, the game's story is finished.
In an interview in the recent issue of Dengeki magazine, it was revealed that the scenario for the game is apparently fleshed out and finalised. This actually shouldn't come as a surprise as the details of the story aren't the heavy lifting, but rather, the actual game programming.
The character designs have also been finalised, and the clothing designs are finished.
Keep in mind that the development of Final Fantasy XIII redirected resources from Versus XIII. So while Square Enix revealed Final Fantasy Versus XIII, the company still had to get Final Fantasy XIII out the door first.
Last year, Nomura said that development on the title was going "well", and the developers were working on various lighting tests for the game.