2 GFX coolers

I am considering finding a couple of coolers to my two 4870. Both are overclocked and idle between 52 and 55 degrees and under load hits like 76-82 degrees. As such, it is not so bad, I have not had problems with the computer crashes or graphics error. But now it is winter, and I know from experience that we will have a summer as hot as in 08 again, it will be easy 30-32 degrees in my apartment and it is with all the windows open and fans to create circulation. That +10-12 degrees for both idle and load temps, and I am not entirely comfortable with.

Does anyone have suggestions for cooling? Requirements are that they must not be more than an extra slot, which is obviously limited considerably.

Although I have seen these:

Zalman VF1000 LED
http://xpriserpic.edbindex.dk/Produc...res/437410.jpg


Zalman Z-Machine GV1000
http://xpriserpic.edbindex.dk/Produc...res/410584.jpg


Thermaltake DuOrb CL-G0102
http://xpriserpic.edbindex.dk/Produc...res/406566.jpg


I would prefer Zalman VF1000 rather GV1000 because of their price, anyone know if there is a significant difference in performance?

Are you sure that the first 2 match in 4780 because they are not on Zalman's website.
Same with the last it is not in thermaltake's homepage.

I think I have seen. Many say that if a fan fits a 3870, it can also sit on a 4870 because there is so much difference in how the mounting holes located between the two models. But I can not find enough good spot has been said anymore.