Maybe I should post in what I did in the shed thread.
I too had beeen looking at the drifta set up ias depicted in one of the above photos but at around a minimum of $1650 I considered my other options. I had seen a couple of mates who have made storage units using the aluminium 25mm tube lock fittings with success and so went down that track.
Yes I know photos are important at this time but unfortunately I have not got any yet. But the bases of the unit fit around of the shelf storage boxes from Bunnings including the Oats range, a fridge slide all fixed to a 17 mm form ply sheet which sits on the floor and will utilise the tie down points of my 5 seat Prado.
It is light in weight , easily put in and out.
I will try and get some pictures this week.