"Square Enix specialty site FF Reunion has a short summary of a new interview with FFXIII art director Isamu Kamikokuryou. In the interview, Kamikokuryou discusses some of the content that was deleted from the game.
Apparently, the FFXIII design team created a number of areas that ended up not going into the final product. How much? Enough to create an additional game, according to Kamikokuryou.
Kamikokuryou shared a few locations with the magazine. Apparently, the design team created a full area surrounding Lightning's home. This area resembled a park. There was also a secret base for resistance group Nora inside a shop somewhere. Nautiuls Park, an amusement facility, at one point also included a zoo.
The content was already running on actual PS3 hardware, it seems, but was left out due to considerations for game volume and overall game balance."
Source:
Final Fantasy XIII Had Lots of Deleted Content (andriasang.com blog, 01.13.2010)