IIRC two more books (twelve total). Having read to book ten, I don't see how he can wrap it up in say 1800-2500 pages without leaving readers feeling a bit cheated. The pace through books 2 to 10 is rather slow, mainly due to his incredible detail and there are too many storylines to wrap up and guide everyone to Tarmon Gai'don at the appointed time. Heck, I'ld feel cheated if the actual event took less than 100 pages itself, and 50 or so pages of afterglow.. er, that is to say, follow-up detailing what everybody does afterward.