A user from the Marathi Wikimedia community (an Indic language, ISO 639-2: mr) has recently requested mailman be translated to Marathi or add support for it to translatewiki.net so that the community could do it.
I replied and pointed to your docs:
See http://wiki.list.org/display/DEV/Internationalization (kinda recent) and http://wiki.list.org/display/DEV/Managing+Translations (ancient)
However, given you seem to be unhappy with your current status quo for i18n on the v2 branch and v3 is (how far away from release? from beta? I have no idea) I thought you might be interested in hearing about a solution that could work with your current gettext files and other templates: https://translatewiki.net
gettext is supported but I'm still inquiring about your templates folder. (e.g.  vs. ). It could be that this requires some additional PHP development, but it's rarely more than a day of work.
You can host it yourself or you can use the hosted copy at translatewiki.net. If you use the hosted copy then you can take advantage of the existing community of experienced translators for many languages who are then able to seamlessly work on mailman strings in the same site they're familiar with from translating other projects like MediaWiki, OpenStreetMap, StatusNet, etc. As one translatewiki.net user just mentioned, "the biggest advantage of having localisations done at translatewiki is its community".
Looking forward to your opinions. We're a heavy user of mailman at Wikimedia, and we care a lot about language support. We have Wikipedias in ~280 languages and Wikimedia has mailman lists in at least ~67 languages.
P.S. I've been lurking in #mailman and I plan stick around there (screen'd) a few weeks at least feel free to send any questions my way on or off list or in the channel. If there's interest in using the site, we can have a meeting with translatewiki.net staff and any interested people from the mailman side.
 http://lists.wikimedia.org/pipermail/mediawiki-i18n/2012-January/000377.html  http://bazaar.launchpad.net/~mailman-coders/mailman/2.1/view/head:/templates...  http://bazaar.launchpad.net/~mailman-coders/mailman/2.1/view/head:/templates...  https://translatewiki.net/docs/Translate/html/FFS_8php.html  I did some rough calculations based on what I could determine guess per list with little work; here are #s of lists per language. not perfect because I only gave each list one lang and there are some with multiple. Used the public list overview @ lists.wikimedia.org.
110 en, 14 de, 9 es, 8 fr, 7 nl, 5 pt, 4 sv ru 3 zh uk tr sr pl ko fi 2 te ta ro no ms mr mk kn ja it hr hi he gu fa cs bn bg be bd 1 vi ur sw sk sah sa pa or nn my ml lb kok km ka is id ia hu hk gd fil eu eo el dk da cak ca as ar als