My Isuzu bed is 6' x 8'6", single cab so at some point we will need at least one box. Only trouble of putting boxes in is it limits the space for brush and logs...working on a custom fix, at least Mr. Bermy is. I tell him what I need, he figures out how to do it, how to make it, then makes it, such a useful chap!
Nothing worse than a half a** attempt a tricking out a truck...
Interesting thing the 'trays' in Oz are almost always aluminum and flat all the way through, you lot seem to have those tubs with wheel arches inside...