I've just uploaded version 31 to my post near the start of this thread
This has no changes for Kindle/Mobipocket ebooks, but adds initial support for Kindle/Print Replica ebooks, outputting a PDF file, and also several mysterious data sections.
The sample Print Replica ebook I have contains only one PDF. It seems from the data stored that it's possible to have more than one PDF stored in a Print Replica ebook. I have tried to guess how this will work, but it's entirely possible that I've guessed wrong, and that the code will need tweaking once someone comes across such an ebook.
As with Kindle/Mobipocket books, this script only works on non-DRM Print Replica ebooks, which at the moment seems to be only the samples that can be downloaded from Amazon.
Feedback very welcome indeed.