One quick question: am I able to modify the registry on the XP CD before it's installed? Like is there a file in the I386 folder that I can extract, load into regedit modify and unload? I want to change a key in HKEY_LOCAL_MACHINE. Is there any way to do this?

Yeah, have a look at the hives and at the inf files. They are called Setupreg.hiv, hivesft.inf and the like. inf files can be directly modified, hives need to be loaded into an existing registry (regedit: Registry / Load Hive).

true, when I do custom os setups, I enter all the info in the setup hives instead of running a program after the os is installed to make all the reg changes. I try to pump as much as possible into the installation so there is less work to do after the os is installed.