That is why I am proud to part of that with my two co authors: Hadrian and Jonathan Anstey. We are writing the book title - Camel in Action, to be published by Manning. Yes its another great book in the action series.
Today the book gone MEAP which means the first 4 chapters is available online. You can read more at Manning what MEAP is. But in terms of Camel you should know that a lot of great documentation and material on Camel itself will go into that book.
For example if you are looking for how to test with Camel, then we got chapter 5 which has 30+ pages on this subject. Actually chapter 5 is online right now.
Since the chapters are not officially finished yet, you can read then in draft form and be able to provide feedback and help influence the book as well. Please use the manning author online forum for this.
Me personally is currently busy writing yet another chapter which is chapter 7 on using beans with Camel.