It seems to me that you could write a command-line program that links to
Mozilla's Gecko rendering engine to render HTML into an in-memory
graphics buffer. Then you could dump the bitmap to the printer, or save
it as a TIFF file or bitmap EPS file.
I haven't heard of software that does this yet, but I think it would be
straightforward to do it. You could even run this from a cron job to
spit automatically generated HTML to the printer every hour or day.
It looks like Gecko's home page is at:
http://www.mozilla.org/newlayout/
Mike