What Tony Bates describes sounds like an exciting project and an English counterpart to the open textbook initiative L3T in the German speaking areas. This collaborative textbook on learning and teaching with technology is the result of the joint effort of 116 authors, 80 reviewers, several proof readers and layout specialists: http://l3t.eu The book is licensed as creative commons and accessible in various digital formats as well as print on demand (which also allows readers to create a personalized selection of chapters). I contributed a chapter on ‘media theory and learning’ to both the 2011 and 2013 edition and served as a reviewer for the 2011 edition. in both roles, I was impressed how smoothly such a large project can be completed. The editors (Sandra Schoen & Martin Ebner) used open journal systems to facilitate the workflow, which worked really well. Though this is usually an architecture for, well, open journals, it can work nicely for books, particularly edited volumes. I like the workflow, with preview, review, copyediting and proofing stages.
It looks like Tony Bates is planning on using PressBooks for his project. A derivation of WordPress, it will output in html, pdf or e-pub formats. I have not worked with PressBooks but it definitely sound like an interesting approach. Many potential contributors will have experience in using WordPress and as such the environment has the potential to provide a low technological barrier for involvement.
Apart from the technological infrastructure, I think it is helpful to provide a template that encourages the use of different instructional elements in each textbook chapter – advance organizers, examples, activities, questions, explorations, glossary terms,…. The platform trello (https://trello.com/) can be a great tool to coordinate the many different tasks that go into publishing an open textbook – cover design, authoring chapters, reviewing, proofreading, layouting, organizing writing sprints, ….
One last thing that I personally would love to see – or rather hear: An audio version of the textbook. I am excited about this idea and have started following Tony’s blog.