Gonna use asciidoc to write my next documentation so I can still have DocBook (not sure why it's so important) and have free ePUB support. asciidoc or any other simple markup language that does the job.
(I'm actually pondering to move the Boost.Python docs from QuickBook to good old ReST, so I could manage all its documentation with the sphinx tool (used by most projects in the Python community). It may lack some features, but the fact that it is well-known by many people outweighs that by far.
Actually, I built a boost theme for sphinx here: https://github.com/pfultz2/sphinx-boost The theme can be installed with pip as well with `pip install sphinx-boost`. I actually use this to generate the documentation for the Fit library. This works quite nicely, and can integrate with other sphinx-based services like ReadTheDocs.org, which will generate up to date boost-style documentation on every push from github. Paul