We now have a very official blue post for the information, Firelands is not part of Patch 4.1. See the previous news post for more information.

Firelands raid will not be in Patch 4.1
Originally Posted by Bashiok(Source)By now you’ve seen that the redesigned Heroic five-player dungeon versions of Zul'Aman and Zul'Gurub are on the PTR, featuring all-new boss mechanics, updated epic-level loot, and some rare mounts for players to try to tame.

You may be asking, "where's Firelands?