I hope that someone is working on that book! I will certainly buy a copy, if it is ever published. And I think there's a need for it -- production of food has been well-covered. Production of
wood for construction and etc. has been covered to some extent (much more in non-permaculture publications, but certainly mentioned in
permie pubs). But there hasn't been much that I've seen on the production of fiber, and since almost all of us wear clothes (probably everyone wears clothes at least some of the time, even nudists), it's a necessary topic.
Kathleen