In the name of the pacing game, Blizzard has confirmed that their Firelands raid will not be part of Patch 4.1
Blizzard Community Manager Bashiok has taken to the forums to confirm that their Firelands raid, where players will take on a newly revamped Ragnaros the Firelord, will not be making it into Patch 4.1. By way of explanation, Bashiok looks back to the content they introduced in WotLK, most notably being the Crusader's Coliseum, and how he felt they released it while people were still entirely too busy with Ulduar. As a result, many players did not get to experience as much of Ulduar as Blizzard wanted, and hence the delay now.
So instead of weeping over the fact that you can't take on Ragnaros with his oddly proportioned legs, you can still enjoy tons of new content in World of Warcraft by spelunking through the newly revamped Zul'Aman and Zul'Gurub instances. Learn some patience, everyone!