Now these sorts of rumours have been right before, with both Dawnguard and Dragonborn having been speculated on weeks before the official announcement, so there is some weight behind the latest guesswork.
|Scimitars and headscarves incoming?||Source|
Their homeland of Hammerfell is one of several countries, such as Morrowind, that share a land border with Skyrim so the idea of an expansion in the border region is entirely possible. More so when you consider that Hammerfell has, by the start of Skyrim, already seceded from the Empire, making it a prime ally/enemy depending on your stance in the civil war.
Now, I'm not actually convinced that the rumours are true in this case. It's not been long since Dragonborn hit Xbox Live, and it has yet to reach PS3 and PC users. My own feeling is that we'll see another extension, with the possibility of this being the title for the next full game in the series rather then simply a DLC.
Until next time friends, let us say Skål! and drink together