Patrick, a thought, you have made one sturdy frame for the door, no question there. However, if you get a side impact, assuming something with a bumper in the middle of the door, it would appear that the door would be pushed in, after breaking or bending the front hinge and the pin the door locks on. It looks like those are the only two solid points holding the door on. Would a second hinge keep the door in place along with some type of L ridgeor lip on inside rear to prevent the door from coming in? It would appear that the door will not "cushion or absorb" much of a blow, just push the entire door in on the passenger or driver, a second hinge and a metal lip at the rear would help transfer some of the impact to the door frame and onto the birdcage. I may be missing something I can't see in the photos though that may already address that. ( you must have been really tired one night, that's the first shot of your shop hasn't been spotless..
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