The earliest one that I have is 27.51 which is on the ELSA 925 driver CD.
Starting from 27.xx, the option is not available, I wrote it wrong in my last post.
Here are the sentense in the readme of RivaTuner
Disabled the 'Enable early Z-occlusion culling' option for the Detonator 27.xx and higher. New drivers ignore this setting and always use early Z-occlusion culling on GeForce3 and higher.