Hey Zac, I'm having this problem too. I have 3 worklings which start at about 50MB and have each grown to about 170MB, which eventually push into swap. I'm also looking for a fix.
I'm using the latest version of all gems (Rails 2.3.3.1, etc.) and still seem to find my workling workers going from 70MB => 230MB about once or twice a day. I have god.rb setup to restart workling when it goes over 200MB, but something must be wrong... I can't figure out a good way to investigate either... any help much appreciated!
Thanks! Aaron