What can I say? I'm flattered, as well as happy to know that people enjoy my writing.
As for an OpenACS book, I'm sorta kinda working on one right now. I recently started work on a book for Apress that compares and contrasts a number of open-source Web development framekworks, including OpenACS. When the time comes, I'll undoubtedly ask people at openacs.org for help as technical reviewers.
