http://www.gameinformer.com/b/news/archive/2012/09/10/obsidian-teases-next-project.aspx

Rampant speculation, go!

I've got nothing. Dungeon Siege 4 seems to be the only likely answer.

The other threads not even off the first page. Poor effort.

http://www.gamesas.com/topic/1410785-obsidian-teasing-a-new-rpg/

The search function has failed me. I typed Obsidian and teases. Nothing.