I managed to get SL retail to install on my rev 2.0 board without too much fuss. First of all, upgrade to the latest BIOS - it seems to resolve a few GSOD issues I had with earlier versions.

First thing I did was the usual DSDT RTC patch - I did this with a Debian LiveCD and iasl.

As for your install media, do the typical thing of copying the SL Retail DVD to an 8+ GB USB drive and then install Chameleon 2.0 RC3 from http://chameleon.osx86.hu/. Replace the /boot file with the PC EFI 10.3 version and setup your boot.plist as needed. Copy your new DSDT.aml over at this point too.

I threw the extra kexts in /Extra/Extensions - all I used was
NullCPUPowerManagement
fakesmc (version 2 from netkas)
OpenHaltRestart

As it stands now, I boot into 64bit without an issue. I don't have audio, or ethernet working yet but I haven't had much time to tinker since I installed on Wednesday. Based on everything I've read, ethernet is a lost cause on the rev 2 board - I'm just going to pick up a $10 PCI card and be done with it. Audio doesn't look like it should be an issue to get it working... couple of kexts and a DSDT patch.

Hope this helps.

EDIT: Forgot to mention, once you're installed, boot with -x32 initially, run KExtUtility, repair permissions, and then you should be able to boot 64 bit.