DocBook to Word Conversion?

Yes, you do need an XSL file. You can get XSL files for DocBook from the free DocBook XML distribution. Then, you run a free XSLT transformer such as Saxon. If you run Saxon from a command line, you give it the name of your DocBook file, and the name of one of the stylesheets, and it will transform your file according to the rules in the stylesheet.

What you need to do to transform to Word, is to pick the right stylesheet.

From DocBook XSL: The Complete Guide, here are three possibilities:

• Convert to XSL-FO and then use the XMLmind to export to Word. See the XMLmind website for more information.
• Use a limited set of tags and then use one of DocBook XML's included stylesheets to output to WordML.
• Try to use Jfor to output to RTF, although Jfor no longer appears to be maintained.

And I have one of my own:

• As above, use one of DocBook XML's included stylesheets to publish to XSL-FO, then run Apache FOP to convert from XSL-FO to RTF. You will lose the structural information, but you will keep a certain amount of the formatting.

I recently implemented same feature for our users. They use Oxygen XML editor that allows for easy transformations via XSL. I was going to do OOXML but settled on WordML. As a starting point I used roundtrip XSL, but I had to rewrite lots of templates because of existing bugs or just missing functionality. In addition, I did other customization to serve a purpose or for our XML file only.

I would not mind contributing back to the project, but don't really know how to get about it.