I was actually about to post about this, I've been trying for weeks and weeks to get 10.7.3 to work with my dual 580's to no avail.
10.7 works fine with a modified chameleon.boot.plist with the EFI string for my cards, although whenever I try to use a program that is graphics-intensive (even just watching an HD .MKV in VLC) the system hangs, sound continues playing and I'm forced to reboot.
I've tried every conceivable install combination, from upgrading to 10.7.3 straight away as soon as I install without Multibeast and then using Multibeast on a fresh 10.7.3, to getting 10.7 to a usable state and then upgrading, to just using the NVidia drivers, to just using the Multibeast 4.3.0 Nvidia 10.7.3 enablers. Nothing works and everything results in the same exact problem, which I've made a video of here:
[VIDEO]http://www.youtube.com/watch?v=0AWI51E_nxU[/VIDEO]
As you can see, after booting, the monitors just lose signal completely and it stays like that indefinitely. Now, before trying to boot into the system without any boot strings I can actually boot into my 10.7.3 system using GraphicsEnabler=No. But the moment that I try to boot without GraphicsEnabler=No this problem occurs, and then every time I try to boot after that, regardless of boot string I try. I'm absolutely stumped here and I seem to even encounter this problem trying to boot into a 10.8 USB stick, so I'm inclined to believe that it has something to do with OSX's new Nvidia drivers interacting with my cards.
Does anybody have any suggestions?
System:
Intel Core i7 2600K @ 3.40GHz
16.0 GB Dual-Channel DDR3
ASRock Z68 Professional Gen3 Motherboard
1536MB GeForce GTX 580 (EVGA)
1536MB GeForce GTX 580 (EVGA)