its actually sitting on the tray with the Ford.. So its actually 260kg distributed on 4 points of contact, so 65 kg on each. Although its high up, and will drastically reduce fuel consumption, its probably well within the Fords load capacity (along with all the other stuff he has fitted to it).
If I were going to do something like that (which I have no interest in) that type of vehicle would be my choice, not a Hilux/Ranger/Etc.