I would like to buy some of these, but the cooler costs are just ridiculous and everyone sells them without them..
My experience is any modern liquid cooler fitted with a high CFM server fans will work fine. The fans the come with the kits are 50-70 CFM and I am including two 250 CFM fans with each board.
Newegg has an entry cooler
http://www.newegg.com/Product/Product.aspx?Item=N82E16835181010