I would love to explore how WikiApiary [1] could help with this. I've started to work on pulling in new user logs from remote wikis. I would be happy to brainstorm in a group on how we could move beyond just IP lists to something more sophisticated. One thought I have had is having WikiApiary use a bot account on remote wikis that wish to participate to fight spammers, revert changes, ban them, etc.
I was thinking along these lines too, although rather than expecting wiki administrators to pro-actively "wish to participate", I was thinking it would be good to have a bot which I could unleash on wikis where I've found spam is taking over (there are many!). This bot could check incoming edits and revert them, and/or do mass clean-up of existing spam.
Do clean-up across lots of wikis and that would possibly deal a big blow to spammers. If you watch that 'ultimate demon' video again, they're building a 1st and 2nd tear pyramid of links across many wikis and blogs. So this is the thing. If you stop spam on one wiki, you're just a minor glitch in their operations. Wipe out their spam from all over the web (as wikis uniquely allow us to do actually) and they might start to view wikis as a less desirable target.
Before developing a de-spamming bot, an easier step might be just to bring things together into a shared recent changes view, to bring some cross-wiki awareness. I hadn't heard of wikiapiary.com, but it looks like it could be a helpful part of this. And a simple of extension of that might be to contact (automatically?) the admins of wikis where spam is flooding in.
Halz