There's Not Going To Be Any Final Fantasy XIII. Probably.

“Regarding the DLC content, we feel that the final product is 100% enjoyable… it’s the complete package. So we’re not planning any DLC at this time,” said one the duo.</blockquote>

It was rumoured a while back that there was enough content cut from Final Fantasy XIII to make up a whole other game. This comment was taken out of context according to the pair.
“In regard to the rumored cut content, we feel it was taken out of context. There are a lot of ideas that are brought to the table, and then the team takes the best ideas out of those, and the final product is polished that way.

“There was content that were ‘ideas’ that didn’t make the final content, but the team isn’t looking to release that as downloadable content.”</blockquote>

So there you have it, no Final Fantasy XIII DLC. Yet. Look out for the re-released Final Fantasy XIII Director's Cut next summer. /snark.