What do you mean "out the back"?
Because it sounds like you are asking if you can cut away the plastic back and metal chasis to create an output where the paper would slide directly through the printer, which quite obviously cannot be done.
This is the back of the 6600, there is no way you could output paper through the back and retain a functional printer.
Beyond that I can't think of a single thing you may have meant by "out the back", but, I apologise if I missed something obvious.
I was hoping you could just flip the back cover down and cover a sensor or pin hole that would allow the paper to somehow slip out the back side without curling around to the top.
I have no intention of cutting anything away.