Simple Question: liquid cooling radiator

I'm always keeping my eyes open for better Hardcore cooling solutions that are fun.

Whats the largest radiator made to work with a computer that you can buy?

A small radiator from an oil or transmission cooler would make a nice computer radiator for an out-of-case application. You should be able to pick one up at a salvage yard really cheap. Maybe use the core of an air conditioner (it has dense fins and lots of coils in the tubing). You just have to rig up some hose adaptors but that shouldn't be very hard, plenty of parts at any Home Depot or Lowes.