[wp-hackers] Related Posts spam?

[Otto]

Is anybody else experiencing this phenomenon?  Basically, every time I
make a post lately, I get hundreds of spam trackbacks to it from blogs
which have the post show up in some kind of "related posts" plugin.

Example:
I made this post:
http://ottopress.com/2010/wordpress-theme-tip-force-an-image-size/
I get linked to from this sort of post:
http://www.thesleepingbagshop.com/sleeping-bags/slumberjack-tourlite-40f-regular-sleeping-bag/

Simple Trackback Validation doesn't stop it because that blog really
is linking to me, albeit by some brain dead algorithm that has
determined that my post is somehow "related".

I've received over 400 trackbacks in this way on that post alone.
Virtually all of them from unrelated sorts of posts. Akismet catches
the majority, but still enough are making it through to become an
annoyance.

Anybody have an idea how to solve or block these?

-Otto