We looked at the xml->xsl-fo->pdf route, and decided instead to use dblatex->LaTeX->pdf (starting from a slightly modified DocBook XML, which therefore required

We looked at the xml->xsl-fo->pdf route, and decided instead to use dblatex->LaTeX->pdf (starting from a slightly modified DocBook XML, which therefore required additional rules in dblatex). We were very satisfied with the result, and were able to do a lot with LaTeX style sheets, including a substantial change in output format when we moved to a different publisher. I should add that our documents were not run-of-the-mill: they were grammars, and sometimes included non-Roman fonts (Bangla) and right-to-left text (Arabic and Thaana scripts). A lot of things came together at just the right time, like XeTeX (think Unicode-aware LaTeX) and good Nasta'liq fonts. Most people don't have those problems :-).