I have a GTX 480 card but the new kexts of Apple will definately work on the Quadro 4000 mac Fermi card.
I am showing a video of OpenCL for my GTX-480 card : Quick Julia (The fps are taken with a dual display 24’’ and 19’’). This is an example of Apple and shows raytracing of a 4d Quaternion Julia-Set Fractal.
You will need Mac OS X 10.6.7 and just google to find out how.