Buy some 5850's
They are not that hot, the power consumption is lower and the price/Mhs is the best.
nmc@nmc-GA-790FXTA-UD5:~/phoenix$ sudo aticonfig --odgt --adapter=all
Adapter 0 - ATI Radeon HD 5800 Series
Sensor 0: Temperature - 73.50 C
Adapter 1 - ATI Radeon HD 5800 Series
Sensor 0: Temperature - 74.00 C
nmc@nmc-GA-790FXTA-UD5:~/phoenix$ sudo aticonfig --odgc --adapter=all
Adapter 0 - ATI Radeon HD 5800 Series
Core (MHz) Memory (MHz)
Current Clocks : 840 900
Current Peak : 840 900
Configurable Peak Range : [550-900] [900-1300]
GPU load : 99%
Adapter 1 - ATI Radeon HD 5800 Series
Core (MHz) Memory (MHz)
Current Clocks : 840 1000
Current Peak : 840 1000
Configurable Peak Range : [765-918] [1000-1200]
GPU load : 99%
nmc@nmc-GA-790FXTA-UD5:~/phoenix$