We have three major releases of the PostgreSQL manual in french : 7.4, 8.0 and 8.1. They are all written in SGML Docbook. We use openjade to convert thems in HTML files, and htmldoc to convert the big HTML file in PDF.
Three weeks ago, friends start talking about migrating to XML Docbook. They mostly did it. I just had some mistakes and a few tags to fix. This done, we used LFS makefile and XSLT files to build the HTML manual. It worked great. But then I told to myself that I should look into building a better PDF manual. htmldoc did a great job with the HTML file we provide but the result was kind of ugly. So I started working on it : fixing some issues in the XML files, adding icons, updating the XSL filters, upgrading FOP.
It took me two weeks to create this PDF manual but I'm very proud of it.