I'm not sure how I missed restructured text. This seems to be Python's answer to POD (Perl's Plain Old Documentation).
After five minutes of looking at it, it looks basically okay. The emphasis seems to be more on being readable in it's text (input) format. In other words, a marked up document is readable even before you render it as HTML, PostScript, etc. That's somewhat in opposition to POD and most Wiki markup (they are very similar to each other) where the emphasis is on easy typing.
I prefer the latter, but maybe with Emacs macros and such the former will be okay. I'm going to try it out.
I bet it doesn't have built-in support for the man page format the way that POD does. We'll see.