Hi Rachel,

I read your article with interest because I am looking for an efficient approach to “write once, convert to many formats” authoring, too.

Have you tried AsciiDoc?
http://asciidoctor.org/docs/what-is-asciidoc/

It is touted as being as powerful as DocBook but without the XML clutter. Free and Open Source authoring and conversion tools are available.

Thanks
Oliver