AlexCeed, nice to see you like WinNTSetup. I agree with you, it's GREAT!!
Just wanted to share with you how I normally use $oem$ folder stuff:
I use the WinNTSetup "-runafter" command line option, to run a WinRAR SFX file, which in turn expands the "Setup" folder to c:\windows after the apply phase. Inside the setup folder is the usual "Scripts\Setupcomplete.cmd" file, and other folders needed for things like activation, etc.
This is a very convenient method for me, because after starting WinNTSetup with this command line, I can even select other SFX files in the GUI, if I need to test other (sfx) $oem$ folder structures. All this without changing the .wim, like you already mentioned.
So maybe this is a bit like the "manual OEM folder selection" you were asking about.
As you see, WinNTSetup has multiple solutions to pretty much anything!
Edited by Atari800XL, 30 September 2015 - 02:07 PM.