Frank --
> I don't think that xml is off topic at all.
Most reassuring.
> but it doesn't go all the way and I guess something like LaTeX still
> has a place in the game;
An XML document type is just a model of a language. I believe that
old designs were optimized for processor writers at the expense of
authors. I have been trying to optimize document type design for the
traditional LaTeX author.
LaTeX itself is the primary back end to paper that I have in mind and
the only one I've written.
-- Bill