Danger Den, one of the major providers for watercooling, has designed the Tyee GPU Waterblock, specifically designed for X1800/1900s.  By making the design so specific, they are able to give some serious cooling coverage with one waterblock.  Take a look at the performance gain techPowerUp! got.
“Danger Den is one of the most established players in the watercooling business. Their new Tyee GPU Waterblock has been designed specifically for the ATI Radeon X1800/X1900 Series and can cool GPU, Memory, Voltage Regulator and CrossFire Encoder Chip with just one block. Even though its installation is a bit complex, it shouldn’t be a problem for more experienced users”

Here are some more Graphics Card articles from around the web:

Click Here to go to Video Cards   Graphics Cards