If there's any hope for the release of a full-length documentary on TMNT 90, it rests with Isaac and his pals at Definitive Films. It's solely a rights issue at this point. There's more than enough historic content on the production to cover a dense documentary or making-of book.
On a related note, keep your eyes peeled for Cleanin' Up the Town: Remembering Ghostbusters! I'm a producer/archivist/editor (and would give my Mirage tail for a crack at TMNT with Isaac & DF).
https://www.youtube.com/watch?v=S5QFRaf6Z1o