Heatsinks and fans for video cards have been around for ages. They are not as popular as they were 20 years ago.
I just happen to be shopping for a new Radeon HD 6850 video card. I read quite a few technical reviews. The stock gpu heatsinks and fans that come with the video card are adequate. If you want gpu temps to drop a little more, then you best bet is the Asus EAH6850:http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=100007709%2050001315%20600083901%20600083830&IsNodeId=1&name=ASUS
I think the EAH6850 DC/2DIS/1GD5/V2 might be a newer version.
Here is a link to a comptent technical review:http://www.silentpcreview.com/Asus_AH6850_DirectCU_VGA_Card
There are more technical reviews but they are almost identical to the Silent PC Review.