User blog comment:Kacj321/Entire Tamriel Landmass built into Skyrim/@comment-108.69.189.4-20111129001525

The most likely to happen in a DLC, I believe, would either be a large island landmass off the coast of Skyrim, or a Daedric Prince's realm. Other than that, nothing really seems plausible, given that it will happen IN Skyrim and Bethesda has officially said that they're focusing on larger DLCs.