a) The ShadowsVisibility is reserved for future use. It would probably control the visibility of all the shadows in the book i.e. if you set ShadowsVisibility="Collapsed" there will be no shadows whatsoever. Does this sound feasible? What's you opinion?
b) If your book is populated with RadBookItems(defined in XAML), you can easily edit the ControlTemplate in Blend and modify the shadows to your preference. If your book is bound, you will have to use the ItemContainerStyle of RadBook. A sample project demonstrating how to use ItemContainerStyle, LeftPageTemplate and RightPageTemplate is being attached.
c) Currently this functionality is not supported. In the example where you thought the content span across two pages, there was actually one image sliced into two - one half given to the left page and the other half given to the right page. I am sorry we mislead you. We plan to support spanning content on two pages, but I cannot guarantee when it will be available.
d) Couldn't this functionality be achieved using RightPageIndex or you have something else in mind? In my opinion, I think it is better to let the user of RadBook(the developer) provide his/her own implementation of chapters/sections logic, because I don't think there is only one correct way to do that. One's understanding of chapters/sections might be different than other's. Also, trying to cover most scenarios regarding this feature would unnecessary probably bloat the dll file.
Let me know what's your opinion on the matter and thanks for the interesting comments and suggestions. Keep the great feedback up.
the Telerik team