Hi!
Have you seen wikiapiary project? [1] Personally I'm fascinated by the statistics of the extensions, and skins. For example here is the stats for Semantic MediaWiki: http://wikiapiary.com/wiki/Extension:Semantic%20MediaWiki You can see the website where the extension is installed and the version information.
Wikiapiary is quite new and I think is open to ideas. For example I think it would be nice to allow people to judge the extensions by several criteria. Maybe also add some code statistics will also be useful.
Please post your ideas here.
[1] http://wikiapiary.com ----- Yury Katkov, WikiVote