Ok, the spammers finally pissed me off enough to go and do it. I finally went and disabled trackbacks for all blogs on my site. In the last 3 days I've gotten over 200 trackback spams, and those things are a pain to get rid of. Thankfully, my blog software is open source and I have full access to the database, so I was able to find the table containing all the trackback spam I received. I went in this table and extracted a complete list of the IP addresses that sent all these trackback spams. I then added these IPs to my site's .htaccess file. This means those spammers are now permanently banned from my site. Once I did this, I was able to go in and in one fell swoop delete all the trackback spam!
You gotta love open source!