EU Cantina got hold of author Elaine Cunningham, who confirmed that the book Blood Oath is for real, and a few more hints:
This will be a very different story from DARK JOURNEY. Obviously, I can’t give any details at this point, but I can confirm that it’s a stand-alone book, rather than an episode in a larger story arc.
She also says we might be getting some kind of announcement soon, but don’t hold your breath.