I have thought of this for adding a k5 top to my burb and keeping barn doors.
You would have to cut away the fiberglass of the cap where the glass slides in and mod it with new fiber glass to hold the burb weather stripping. MY Idea was to graft in the bed side piller, tube or a 1/2" plate up the piller and down to a cross bar welded from side to side this will add the needed strength and a place to mount a slightly lowered hinge.
My other idea is to modify the barn doors other wise with you take the cap off you would have to doors sticking up.
the idea would be to cut the doors in half, then cap INside the doors with plate, top and bottom, this way you could bolt the doors together, or in half when the top was off so you would be left with a barndoortailgate