I am using a modded bios (1.10) from here: http://www.osxcores.site50.net/ that solved my boot hanging. (I do not need a dsdt.AML for Leopard, but it seems I do for Snow Leopard)

Switching to compatible mode gives me both SATA and IDE in both Snow Leopard and Leopard...just switching to that mode avoided a Kernel Panic upon boot up with Snow Leopard.

As for my network controller, I use this kext from Realtek

http://www.realtek.com.tw/downloads/...etDown=false#7

I only have 2gb of ram so it might confirm your theory