The bottom luggage would be 36 inches wide and split into two elements (a tent and a chair both in stuff sacks) and the top case would be 26.5 inches wide weighing 30 lbs with up to 20lbs additional stored inside.
I know the proportions are a bit off, but is something like this possible? I would put some padding on the back of the box on top for passenger to have. Figured I would ask here before I go all in on this idea from my touring trip. I would only two-up very occasionally. I would hire a welder to make it.