I've done a successful install of Leopard (iAtkos_7) on my M17x with the following specs:
Dual 260M SLI
4 GB RAM
I followed your guide - thanks very much for posting this! It sees the CPU as an Intel Xeon Quad Core, and recogizes two GPUs (using one). Sounds works great. I primarily use OSX86 to run Everquest Mac edition and it's very smooth with max settings and sound working. My Belkin N52 gamepad works fine as well.
Now to properly configure the dual boot - right now I have the OSX HD as the first in boot sequence, and I have to F12 to get Chameleon to come up (thought that was odd) to choose boot drive. I'll do EasyBCD today, assuming that Win7/OSX86 on separate drives won't be an issue.
I'll check the HDMI on an external display this evening also.