I've had a lot of good luck with using the generic Hayden transmission oil coolers in the past. I'm running two of the compact car version in my fanless WC system and they handle the vid card and 2.4C at 3.2 very well.
Here's a pic
I spent a very long time looking for the perfect cooler for my
new project and came up with something very interesting, the Fluidyne FHP-10026. I've never seen anything like it and so asked them for some pics of the tubes and turbulator.
My gut feeling is that it looks great if a bit restrictive, but I'll let you know how it turns out once I get the system together. I'll probably be running two in parallel due to the design of the case I'm building.