SGMLtools is a text-formatting package based on SGML (Standard Generalized
Markup Language), which allows you to produce TeX/DVI/PS/PDF, HTML, and RTF
from a single source; due to the flexible nature of SGML many other target
formats are possible.  As the front-end is written in Python, it is relatively
easy to adapt to your needs. 

WWW: http://www.sgmltools.org/