Well thanks for the help anyway. It does seem like a specialised topic (and I'm very prone to very weird errors, so this isn't the first time someone else threw up their arms).
I've not heard of this tool, but our use is pretty specialised (we're embedded) so we need to strip, add and modify components (drivers, shell, etc) for the image. Does SCCM allow it? I don't mind giving it a try.