Hi Brian
I considered the "creating a course and adding all users to it" as a solution, but really didn't want users to have to put up with having an extra course on their list.
Thankfully I work with a very talented multimedia developer and she managed to come up with a solution. It isn't particularly pretty, or even best practice, but it does produce the desired results for the user. My limited understanding is this; when a user that is enrolled in a course logs in, the course list refers to a div class called "unlist" which displays only the courses they are enrolled in. If a user that is not enrolled in any courses logs in the the course list refers to a div class called "box categorybox", which displays all the courses. She manipulated the theme so that when the "box categorybox" div class is called up it presents a "No course information to show" message instead.
Like I said, by her own admission it isn't the best thing to do but from my perspective it achieves what it needs to.