I just bought ProxyLeech.com.
Unfortunately, it's built using VB.net. This means I'll have to find some Windows hosting until I get this recoded to work under Unix.
It's a pretty interesting little site. It focuses on port proxies, which is quite different than my usual focus on web proxies. (Terminology gets a little clumsy here...)
Proxies currently have to be added manually, but they are checked automatically.
Is there an off-the-shelf script with similar functionality, or will I need to have something custom coded?