Final Fantasy Versus XIII was announced by Square-Enix at E3 2006 as one of three games in the Fabula Nova Crystallis series (Final Fantasy XIII and Final Fantasy Agito XII. This is probably the period when SE was the furthest up its own ass.
Flash forward seven years, and FF Versus XIII has been renamed Final Fantasy XV and is coming to the Playstation 4 and Xbox One sometime in the future. It went into full production in 2010, if sources are to be trusted. A PC release has not been mentioned yet.
Here's the trailer shown at E3 2013:
And the second, dubbed Battle Gameplay Trailer:
As a huge fan of the series, but one who hasn't finished a core game since FFX, I think it looks spectacular. I truly hope they get this right, as I don't think I've ever loved a series like I did FF from 1994 to 2000.