An intelligent flatbed setup (what I think the Australians call "trays") is usually way better than a regular bed (barring maybe aerodynamics). A good Bradford or Circle D flatbed (as examples) can take way, way more punishment than a regular bed, and it's real easy to bring a forklift up and load pallets on the side, add boxes or tie downs, etc. One major reason you don't see a lot of them in the states is that many insurers (if you tell them you've put an flatbed on -- even a pretty aluminum one on a mini truck) will automatically assume the truck is being used in some sort of revenue service, and charge you significantly more expensive commercial rates no matter what you tell them.
One of our favourite bits of kit is a twin axle trailer my father built back in the 1970s.
It's got slaved brakes (electrical now, once hydraulic), Hayman-Reese family anti sway bars, uprights and rings on the tow arms to hold gas bottles and spare tyres, and a flat bed.
The smart setup there is removable side and back walls to convert between flat tray and shallow box with sides, and a removable hood with three gull wing doors (so that the tray is a lockable and weather proof space (useful for camping). It's easy to change configuration between the three states.
Our prefered vehicle of choice is a four door family sedan with boot, the trailer can be added for those odd two tonne loads of manure, gravel, straw, sand, etc that get carted about.
Everything else starts getting into dedicated task vehicles - tractors, harveters, chase trucks, etc. The last thing we acquired was an ex military twelve tonne truck with shoulder high tyres on it and enough clearance for pre schoolers to walk under .. it can climb hills, waddle across gullies, and carry 5 tonne of water for fire control (the reason for purchase and fitting).
