Project Rapture. The supposed shots were leaked to the Final Fantasy XI Online staff by a source close to the game's development team.
According to Allakhazam, Project Rapture will be using Square Enix's Crystal Tools graphics engine and will be released on the PlayStation 3, Xbox 360, and PC.
If you ask me, it looks like an online version of Final Fantasy XII, with slightly improved graphics. Take this with a grain of salt, tomorrow is April Fools.
[Sneak Peek at Square's New MMO!]