IMO with 5 120mm fans you should looking for a card with an open design that cools itself well and let the case fans deal with removing the hot air. The HD6850 is quite power efficient and doesn't produce much heat so it shouldn't be a big deal anyway, even if you crossfire.
This would be a good choice; http://www.newegg.com/Product/Product.aspx?Item=N82E16814121419