And because it's wikipedia, we can harvest this data all the way back in time!
Have fun :)
which links to
Honestly, I just put anon together in a few hours, and didn't put a great deal of thought into it. It might make sense to do what you suggest, and create a more generic webapp to deploy on Wikimedia labs, which manages the IP ranges, and Twitter accounts to post to.
What would really be interesting are edits made from known Tor endpoints.
Nothing tweeted yet except mention of the US Congress one, corresponding accounts also for Canada and Sweden and a mention of IFTTT and code at https://github.com/edsu/anon
(linked from the first tweet by @congressedits)