There is a new web service for single source publishing learning materials called CourseworkerXML www.courseworker.com. It supports DocBook (and other XML sources). You can develop course materials locally with your own XML editor (XMetal is supported), upload the XML master and figures into your own private workspace, and get Courseworker to batch generate the print, PDF and HTML/web publications you need. The quality of output is very professional.
It has to be setup first though, to accommodate your preferences (style, structure etc) and is really for teams producing whole programmes rather than individual tutors producing modules. It does support Moodle XML for assessments though, so you can single source those too and link them together with the core course materials.
It's used to produce the big eMBA programme at Edinburgh Business School, so has a pretty powerful batch pagination engine and HTML tree generator. That programme outputs in Chinese and Arabic too - still using DocBook XML masters.
There is a Moodle CPD demo showing courseworker outputs here: http://www.coachesinfo.com/index.php