http://www.mediawiki.org/wiki/MoinMoin
Covers most of what we've talked about in this thread, links to similar discussions on moinmo.in .
The workplace effort to fully convert the old wiki from Moin to MW has been abandoned, after we ascertained that most of what was in the old wiki was outdated enough to be literally worse than nothing ;-)
So we're currently porting information over from the old wiki one page at a time, as said page is checked for up-to-date correctness. To this end, I've written a crappy Perl CGI that uses the Filter() subroutine from the Littlejohn Consulting mm2mw.pl script, with some tweaks that I'll be adding to the above page in due course.
- d.