Took some measurements and the setup in the photo should fit with no issue. One idea, set the tray on rollers so it can be pulled out to the side to allow access to the front storage area and possibly have a stand to operate generators. They would pull out to the drivers side - same side as our power. Maybe have some adjustable legs for support and lock to secure everything.
Going to connect with a buddy who does high end cars (they built a Mustang for Buster Posey) - he should be able to point me to a fabricator / metal guy.
2020 International Serenity 27FBT
2018 F F250 Lariat Ultimate
2017 Shelby GT 350
2015 Grand Cherokee Summit Eco Diesel