referral spam

I was browsing through StatTraq’s summary page and noticed a bunch of nonsense links that look like they’re straight out of one of my comment spam blacklists. None of the programs out there seem to catch “referral spam,” at least none that I’ve seen.

If all this stuff is getting stored into a WP database, then surely there must be a way of creating a referral blacklist to catch them before they get logged, right? Anyone know of a way to do this?