Just recently, the Patoline project (http://patoline.org/) seems to have regained activity. Since I’m very interested in it I’m writing this post so that others may learn about its existence.
From my experience of writing a mid-sized document (internship report) with Patoline, the tool is very nice to use (especially for OCaml programmers) and very promising! However, it suffers from a few shortcomings typical of free software projects: lack of advanced documentation, and obligation for the user to learn about the software’s internals when they want to customize their rendering in unusual ways.
I hope to find some time to contribute to Patoline this year!