Hey, GMONIZ -- How would I find them on eBay? What search terms?
I'm thinking of a small container, like the size of a tape measure, that would sit on the side wall of the bed with the cable rolled up inside. The cable travels 3-4 inches to the tailgate and that's all you see. Open the tailgate and the cable rolls out of the container, holding the tailgate at a 90-degree position. Close the tailgate and the cable rolls up, back into the container.
It's so simple, I can't believe it isn't out there!