Ran across this site a few days ago, they log ip, username and domain info and provide an sql doc to load to banlist. Seems to have loaded just dandy, though it is a couple of thousand entries, I recognized several domains I've had trouble with. They also have a lookup service for names in their database if you're not sure about one. Let me know what you think.

Stop Forum Spam - Spammer Domains

Of course, I think you might already know about it...

Thanks again,
JL