Actually, killing your service when it's overloaded should prove to be a good load balancer over the long term. Initially, the server will be killed a lot, preventing users from using your service. At some point, those users won't come back anymore because your service is so bad (unless it's Twitter), and you won't need to kill the server anymore. Eventually, you won't have any users, so you won't have any load problems.

I will stick with Perlbal, however.