I have a project where I need to create output in HTML, plaintext, Word doc, RTF, and PDF formats. The Word doc options seems particularly annoying.

A clean solution would be something that allowed these different outputs from the same source in XML, Markdown, or something like that.

The requirements are that it must run on UNIX, it must work with Word 2000 and forward, so the 2003 WordprocessingML format won’t cut it, and I prefer free and open source solutions. Something that has a good API in Ruby is nice, but not required.

Do you have any pointers to help me get started?