Frankly at this point, I don't see why Google couldn't be made aware of the WikiPress project for de.wikipedia, as they do have ISBN numbers (for admittedly German langauge content). And you can order any of those books from Amazon.com or any other retail bookstore if you are interested in it.
-- Robert Scott Horning
I'm wondering if google wouldn't already be aware of the de.wikibooks published books, especially if they already do have ISBN numbers, and if they are available through amazon. I don't know any german, but maybe somebody who can speak it should do a quick books.google search for one of the published books, to see what kinds of things turn up.
--Andrew Whitworth (Whiteknight)