It just occurred to me, Jim's written a Spider-man novel, Kevin Smith has written Green Arrow comic books, a graphic novel would be an interesting direction to go.

The Star Wars novels also tend to be overseen by an editorial board that plans storylines, then has authors work on those lines; the New Jedi Order series was done that way.  R.A. Salvatore received a lot of hate mail over the events of Vector Prime, when it was the board and Lucas that mandated said events.

As far as fan fiction/parallel fiction goes, I don't quite get the allure.  I understand paying homage to a writer and his creations, and Jim has created something really special here.  But here's the catch - such stories can be kept out of these forums easily enough.  Still, people are posting elsewhere.  And if in a future Dresden novel "X" occurs, and someone wrote something similar to "X" and posted it somewhere, there will be the feeling that the idea was stolen.

Some years ago I was working on a science fiction novel, and had a ship caught in tractor beams.  The pilot escaped by firing missiles at the capturing vessel to break up the beam.  Two years later something very similar showed up in a Star Wars novel.  Even though there was no way that author could have know about my idea (my writings never approached the show-to-my-friends state, much less send-to-publishers), I still felt cheated.  At the very least, I knew I couldn't use that scene, because I'd get hit with "so and so did that exact same thing!"

Im guessing that, like most series or book related RPG damges, it will only have one Book. It won't have a core set or many supplemant books, like D and D does.

Probably so.  Most of the RPGs I've played have one main book, divided into player/game master sections.  Even Star Wars, which is published by WotC does the same.  Of course, if the game takes off, then we can hopefully look forward to supplements, such as extended bestiaries, city guides, and the like.