Door within a door

Has anyone built a door within a door? Is this reasonably feasible for a foamie? Am not married to this idea yet but it has appeal. In one of his old Popular Mechanics, BF found a photo of a camper with a rear hatch that had a door built into it. The hatch lifted up for loading items. When hatch was closed you had use of a smaller man door. This is my crude sketch of it:

My original idea was for barn doors. But for these to open wide enough it really takes up most of the back end. Was wondering if that would leave the structure of the rear a bit weaker. Was thinking that with the door within a door idea the rear would be stronger with the hatch closed tightly than with the two separate barn doors, one of which is constantly being opened & closed.
It's just an idea. Wondered what others thought.
My original idea was for barn doors. But for these to open wide enough it really takes up most of the back end. Was wondering if that would leave the structure of the rear a bit weaker. Was thinking that with the door within a door idea the rear would be stronger with the hatch closed tightly than with the two separate barn doors, one of which is constantly being opened & closed.
It's just an idea. Wondered what others thought.