As shown in the pictures, on both sides of the car between the rear wheels and the doors, I need to cut out and repair the rust. I know I can buy outer skin patch panels for the exterior sheet metal but my concern is the structural members that are rotted out. As you can see one of them is completely rusted and has been cut out. Are these pieces available on the market or do I need to just fab something up to substitute for them? If so what are they called and where do I get them? I know I will need to cut some more of the metal out and have concerns about access to weld new members in. Any suggestions is what I am looking for.