Oh Dear,
I'm now itching to modify my TR door skins. It could be done.
Cut the door chassis at the flange with the skin so that the flange stays with the skin
On the detached skin, weld on a new flange assembly protruding from the door skin - this slides onto the door chassis.
Drill and locate a good number of rivnuts into the door chassis to hold the door skin.
There is certainly room to play with
Roger