Depending on the nature and scope of the project, I have had a good deal of success using, for instance, a MySQL database, Perl, and QuarkXpress on a Mac to do business cards for a 150+ person company.

And while this doesn't really sound like what you want, I thought I would mention it just in case as it's a poorly-documented solution of which many are completely unaware.

Essentially you play to Perl's strengths, using it to parse the text/db output/HTML/whatever and perform basic markup functions/regexps using Quark's style-sheet markup language (see deep in the Quark Appendices). Quark allows you to import with style sheets and there is *nothing* that you would ordinarily do to text in Quark that you can't do using the markup language, and you can then add images, etc., to your final product (not a bad thing for long documentation, business cards...).

If anyone is interested I'd be happy to explain some of the strengths and weaknesses of this approach off-list.

Otherwise, if open/free is the criteria, LaTex is definitely worth a look.