I'm honestly baffled as to where they got that idea, most commercial vans are built around standard pallets and wallboard sheets. Mercedes Sprinter and Vito will, the Transit including the Transit Custom will, the Toyota Hiace will, it's pretty much a standard feature.
As in plasterboard sheets? I don't see why not if hand loading, plenty of vans will fit a 2400x1200 sheet (my Transporter fitted a bunch of plywood with room to spare). Loading one with a forklift is harder due to no side access long enough to fit 2400mm but that's a problem shared with tub back utes. If however your plasterboard pallet is side accessible a van with barn doors (like you'd buy if pallets were a priority) will allow you load it in fine.
Actually yes my ranger fits just fine in some of the tightest of places. Never had a problem fitting into compact car spots with no over hang. With a full size 8 foot bed no less.
cupcake if you think that's how I'm loading that into my truck you're the idiot
Did you know there's actually space between the wheel tubs in the bed of that truck to set those boards down flat. And if your object is still a little wider than that you stack a couple of pallets underneath it to build up to level with the wheel tubs and then load it on top of those still within the bed rails and sides and wouldn't necessitate having to try and do a side load like this. where your loading over the side you use a sling and don't just use boards like a fucking idiot.