I have one inspiration which springs to mind.... sell it!
keep the standard unimog one, and spend your time doing something else. Aluminium and steel put together isn't a good mix without isolating it from each other to stop corrosion.
280 lts is around 250kgs as well, so it's going to take more fuel carting it around.
You may have a good point there, Ed... actually several good points... lol