Mental exercise, I want a gin pole.

[Dr Dean]

My service truck is a 2017 Ram 2500 long box. As of now the boss says no way to take the box off and put a flat bed on.
What I would like to do is build a frame for inside the box to secure my tool box at the back of the bed, a 25 gallon oil tank that is 16" diameter ~36"tall, a cross over tool box and gas power air compressor. If I actually build the frame the cross over tool box will be replaced with a box that goes all the way to the floor since the space under the box I have now is basically wasted.
I plan to anchor to the tie downs in the box and utilize the frame and tool weight to act as a counterbalance to the crane. I want to be capable of lifting 1000 Lbs 16 feet in the air, this way I can handle augers on combines, I don't need to be able to move the truck when in use I can move the machine. The rules set out by the boss, I can not drill any holes in the box and the tailgate has to stay.
I already have a piece of 1/4" plate that folds down to cover the tailgate. I also have 2 2000 Lb ATV winches.