I just got 10.5.1 working all peachy thanks to your wonderful little guide.
It's been...an adventure.
I went through two botched installs because I was greeted with a blank screen and a flashing cursor twice; the bootloader didn't install. I was confused and then decided perhaps the Kalyway CD tripped over itself somewhere (I presume that's what it's for, installing the bootloader), so on my third attempt I used one the other disk utility on there (the ASR one, I believe), to temporarily format it as GUID to nuke the MBR table and then reformatted the disk using the proper disk utility, and I did a test boot (before installing), and sure enough, the darwin bootloader came up spouting an error about not being able to find some plist file (boot config, I presume). Success. I then installed the BrazilMac patched DVD, and, in case pc_efi was FUBARing the bootloader, I did the regular patched install first. Booted perfect. Afterwards I booted into single user mode to set up pc_efi and replaced the proper kexts as per the guide, and presto! it works. I'm not sure what went wrong the first two times, but I'm damn glad it works. Did the software update, and it's all operational, as if it were a real Mac.
Also, as a bit of advice, when you first put in the BrazilMac DVD (or whichever patched setup you're using), open the terminal and copy over all the data you put on your flash drive for this project onto the hard disk you want to install to. That way, you can simply use the terminal in Kalyway the second time around, therefore saving you a lot of time, as it boots much faster than the install DVD.
It's been fun.