I used to process DocBook at ANSYS,Inc.. Currently, I'm working in a small development company called Webmedx in Pittsburgh, Pennsylvania. I use DocBook to maintain some of the internal documentation there, but it isn't the main focus of my work, hence my sudden disappearance from the DocBook community near the end of 2003.
Here are a few projects that I worked on during my time at ANSYS. Perhaps at some point I'll have time and inclination to do something else:
Html2DocBook: An XSL stylesheet for transforming XHTML to DocBook
PageNumberPrefixes: A Customization layer for creating FO documents where page numbers are "prefixed" by the chapter number (e.g. 'see page 6--3')
CustomizationLayerTemplate: A template for creating Wiki pages describing customization layers
Quick Reference Card: A PDF file containing a list of DocBook elements, arranged by category. (DavePawson arranged the elements; I made a few minor modifications.) Jeff's copy replaced by the one on the docbook faq. I have the source XML if needed. (DP)
I also had a working transformation to convert '<mediaobjectco/>' into HTML image maps.
I don't have the source code for that anymore, but I might try to recreate and improve on it at some point.
Contact him by e-mail: Jeff Beal