windowing system built on OpenGL?

Has there ever been any serious attempt
at creating a windowing system based upon OpenGL?
It seems like a logical next step to do
such a thing.

It may be slow on older systems but at this point,
most of those computers are headed for the recycling
service and there's little to be done to stop that.

So we are stuck with faster computers that
can generally handle OpenGL fairly well. So...

What if one were to model the window concept
as a polygon with a texture on it?