When the first Artemis Fowl book came out, there was a secret code in the book that was supposed to be an entry for a walk on role in the movie adaptation. Years later, I am still waiting for the movie.
I have long felt "In The Net of Dreams" is an under-appreciated masterpiece, and would be an awesome film, if done right.
The DC comics character "Static" (originally Milestone, but migrated into the main universe) was strong enough to support a multi-year animated series, I think he could support a feature film. And then tie it into the JLA movie.