Hi Jan,
1. Nameing and organizing the project, product and environments files. I am currently reorganising the files for my cooperative. I think that besides some nameing conventions it is more or less up to me how I organise our print work. Any recommendations welcome.
Download "themes.zip" from the blog post. It shows some naming conventions and relationships between projects, products, environments, and components.
books. What I am looking for is a script to extract all XML tags/tokens from their files to have a complete list of things that should be handled in a ConTeXt style file. Five years ago I tried to create such a style file by hand, but I gave up.
XSL was designed specifically to parse XML. ConTeXt has facilities for mapping XML tokens, as you've used. Depending on the complexity of what you're trying to accomplish, take a look at "book.zip" from the blog post. Inside you'll find "se2md.xsl"; a similar approach could work for TEI: put the complexity of parsing TEI into XSL, then use ConTeXt to typeset the resulting document.