GPU rendering works, but use the Hybrid sampler, not Hybrid SSPM.

I've also tried it and I watched it for a few minutes gobbling up all my RAM and then it started filling up my Hard disk with Virtual memory blocks.. when it hit about 20 GB of RAM used I killed it. :p

Software: OS X 10.8 - Poser Pro 2012 SR2 - Luxrender 1.0RC3 - Pose2Lux
Hardware: iMac - 3.06 GHz Core2Duo - 12 GB RAM - ATI Radeon HD 4670 - 256 MB