Blocking comments that originate from anonymous proxies

For the past several months my website has been on the receiving end of nasty comments left by a stalker who utilizes anonymous proxies to get around my IP bans.

I was wondering if anyone knows of any maintained and working plugins for WordPress that work kindof similar to Spam Karma or something in that they check a list (ideally as many lists as possible) of anonymous proxies online and automatically refuse comments that originate from these places.

I found this one and installed it but I’m not 100% certain that it’ll do what I want and I haven’t heard back from its creator yet.

So any ideas?