Non GUI based progress bar

How can I make a progress bar appear in Unity that doesn’t make use of the OnGUI functionality in C#?

I’m doing something with an Oculus and the OnGUI stuff doesn’t work too well in a stereoscopic setting. I’m open to hear suggestions or try code samples as I can’t seem to think of a way to display this in Unity and every google search brings up OnGUI examples.

A simple and somehow sounding a little stupid is to use a plane that you attached to the camera…

It is like the google…googles(?) Those new glasses, anyway.
You have the plane in front of your eyes and it follows you around like a GUI.