Rumors about this have been floating around for a long time. I don't have any first hand information on the topic, but I will throw out what I heard with the hope that someone who reads this (and we all know that you are out there) will either flesh out the information I have, or set the record straight.
The book was tentatively titled
Private Agendas, and the action centered around the political goings on in the North American Tir. In the book it explains how Anthine Oakforst's son is killed, and how Lowfyr leaves the council, amongst other things. Presumably a lot of the weirdness with the horrors almost coming through is all tied up with this as well, and brought to some sort of conclusion, including the death of the Big D, blood mages in Azzy, etc....
I would also like to say as a personal note (and my other reason for writing this) how sad it is that this book was never published. Mike's work has provided so much wonderful fun for myself and so many others that he should have been given a chance to add to the novel line. He was also one of the few people in the gaming world (not something I admit I have ever been a big part of, so don't take offence please, most of you I don't know and have never interacted with) who, during the old FASA days, was generous, prompt, and polite in responding to email questions about the game and the direction it was going.
Hopefully this thread will get more information about this out there.
AFE