Well.. I can get the buttons and their functionality to work properly in the full-screen mode.
However... I cannot get the actual button graphic to appear. This is because only one image is loaded here.. and it's a sprite image of the tinymce buttons. Most of my buttons are custom.. and have their own button image.
If WP provided a way to also hook the button image into it's class... then I could probably make this an option. However, WP only allows the buttons name, it's title, and it's callback function.
So.. we are going to have to wait and see if WP will change it's class function and allow the button image to also be used.
I'm going to mark this as Resolved. But I'll certainly keep my eyes open for ways to make this happen.