Is that something you will have to fabricate yourself? I would think so...
Depends on the door - early doors I think you'll need to fab up, I haven't seen an aftermarket skin for them. On the later doors, a couple of different cruiser parts houses carry them. CCOT and Real Steel Cruiser Parts that I know of (probably others). I'll likely be going Real Steel as I've heard good things about their fitment. I'll probably be ordering soon because their business is for sale, which makes me nervous!
Front door patches kits - Real Steel Cruiser Parts