It sounds like a fantastic idea, Matthew, and I certainly agree that Codeigniter has some of the best documentation I've come across with, so it could act as an example to aspire to. In my opinion, and as Soma mentioned in another thread, the main problem novice users face when looking for information is that, more often than not, they don't really know what to look for, so the odds of them finding the right info are pretty slim. I really believe that having 'how-to" articles that address a wide array of different case scenarios would help diminish this problem, and make the current documentation more beginner friendly.
The small project walkthrough tutorial that Ryan posted some time ago is a superb example of how this can be implemented. This tutorial helps ProcessWire newcomers understand how the most basic actions are executed in the system, and provides information that will be of use in projects that go far beyond the scope of the case study Ryan proposes. I can say this tutorial helped me understand the system.
In my opinion, ProcessWire's documentation is already quite good, but I think, looking at the future, we should go the extra mile to make things easier for those users with less experience with PHP. As it turns out, the number of designers using ProcessWire seems to be growing, and this can only be regarded as a good thing. Adding a collection of project walkthroughs, or how-to articles to the documentation, be that through processwire.com or through any other website, is going to make ProcessWire much more attractive to a much wider audience. This is just my opinion, anyway.
Claudio