if u're looking for a voltage that isn't 12V, 7V or 5V all u need to do is to get one of these babies
Zalman Fan Mate a zalman fan mate one, it's what comes with the Zalman heatsinks and they allow u to run the voltage between 11V and 5V and the have RPM monitoring wiring as well so u can still monitor the RPM on the 3 wire fans