Apple Kills the Textbook with iBooks 2, iBooks Author

[Spike89]

59. Lesson plans aren't textbooks

However, I think you have a valid point. Some curriculum areas and teaching styles will more easily convert to an environment where lesson plans (original and collaborative as you describe) and multi-sourced online reference materials will provide both the structure and knowledge base that currently is provided by textbooks.
What I don't really see is an e-book equivalent of a textbook being the long-term answer. E-books do not solve the fundamental problems of traditional textbooks (cost, potential bias, regimented resources). Your idea, taken a bit further with students being guided toward finding their own knowledge over the internet is much more promising in my opinion. Of course, it does have the disadvantage of being a model that the for-profit education industry will have trouble getting money from.