http://www.youtube.com/watch?v=VVqjGteog4I

0:30 to 0:40 shows a magic staircase going to a nightmare world. My guess its a gate of oblivion that goes to Molag's house.

His twisted version of Tamriel? Yes, that was my theory exactly. But why would he have an Elder Scroll? I'm just guessing that's why we're going round for tea and sweetrolls.

There is a thread on it here: http://www.gamesas.com/topic/1377678-to-feast-on-the-souls-of-the-livingand-the-dead/

I think it may be some twisted Sovgarde place, or Molag's drawing room.
He does seemed to be involved, or at least its heavy speculated that he is... and with the ESO being mentioned alot with Molag as on of the main bad guys, it does seem a little bit too coincidental

You know what I think you are right!

While I'm pretty sure they're going to go the Bal route, don't forget that Vaermina is tied quite closely to Vampires too. She's the one that Bal goes to for the cure after all. It's likely Vaermina made the curse and Bal spread it.