I had started a mediawiki bundle, which has not gone much further than copying from the markdown bundle, but at least one person asked me to make it available. Since I am not really very proud of it as it stands, and since I am not planning to work on it much in the near future, I won't add it to the repository yet, but if you want to download it and use/improve it, point your browser here: http://skiadas.dcostanet.net/uploads/mediawiki.zip

Haris