I am using extra cameras in my GUI to inspect items. I would like for the camera to be drawn on top of the OnGUI stuff but instead the GUI is drawn on top. I'm using OnGUI to draw the GUI, is there a way to draw the camera on top of that?
No.
That's not enough text to be allowed to post, but that is your answer.
Although you can achieve some of that effect by having the camera render to a texture and then drawing that. I've experienced poor performance doing it, but it's worked.