I've just created a separate mailing list for discussion on the proposed Wikipedia / Wikimedia-based textbook projects. Those interested in this, please sign up at: http://mail.wikipedia.org/mailman/listinfo/textbook-l
If someone more into the subject wants to take over administration of the list, please do. (It's the usual list admin password.)
-- brion vibber (brion @ pobox.com)
wikipedia-l@lists.wikimedia.org