Now that I've had some time to sleep, I may offer better advice...
The Cegui included with the Ogre source code is sufficient for the Ogre samples, but it is not sufficient for programmers that wish to develop GUIs using Cegui and Ogre. However that may not be a big problem. Here's what I mean (yes this is relevant, no I'm not just showing off).
I'm currently "involved" in multiple projects that use both Ogre and Cegui. Each project has a separate directory:
root
--MyPersonalProjects
----MyProject1
----MyProject2
----MyProject3
--Cegui
----Cegui_Head (svn)
----CeLayoutEditor (svn)
--CeguiTestBed
--ogrenew (cvs)
--ogreaddons (cvs)
--OgreTestBed
Within MyPersonalProjects are separate projects that contain a subset of the Ogre and the Cegui resource files. These are used until I replace them with my own media. There is
a separate CeLayoutEditor.ini per project, since they have access to different media; imagine a kid's game with a cartoonish GUI, a business GUI, and a game GUI.
Yes, I'm copying some of the contents from Cegui and Ogre into multiple directories rather than using a single, unified location/source. And yes I have to update those contents whenever the media of Cegui and/or Ogre changes into multiple directories. That's a hassle, made simpler through batch files, but in return (as a positive) each CeLayoutEditor has access only to the media relevant to that project.
My argument is that the CELayoutEditor should not point toward the Ogre media nor the Cegui media but should instead point toward the directory structure that will actually be used within your project. Of course if you are an Ogre or Cegui core developer then your needs are different, but that's the minority; for nearly every programmer I argue that they should create their own directory structure for use by both the application and CELayoutEditor.
Here's another tidbit of information. The CELayoutEditor.ini specifies multiple directories. However Cegui applications can also use multiple directories:
DefaultResourceProvider.
Incidentally, CeguiTestBed contains every tutorial that has been Wikied and OgreTestBed contains every tutorial as well as some snippets posted in the wiki or on the message board. These "test" projects make it easy to test out a feature before incorporating it within my "real" projects.