Replating caravans has only a limited market as many caravans are sold with a MTPLM which equates to the maximum weight allowed by the chassis maker, so no upgrade possible., unless you indulge in a very costly change out of the axle rubbers.
What I find basically incomprehensible is that many manufacturers will happily sell vans when they know full well that to take even an average amount of equipment, will overload the van, but as long as it sells, they do not care. This is an area where magazines such as yours have been negligent in ignoring the obvious, and one has To assume this is due to commercial pressures. I noted an article recently in a sister magazine on a 4 berth motorhome where the magazine decried the'low payload of 350 kg' but did state a chassis upgrade was available to increase this to 600 kg. Now if a motorhome magazine feels that 350 kg is too low for a 4 berth motorhome one can only wonder at how they would view a caravan for 4 people with a payload of less than 200 kg. One could of course argue that some weight can be put in the tow car, but even here a maximum of 200 kg is probably the very tops.
If just one caravan magazine would actually test a van realistically, not just runoff to the pub for meals, thereby conveniently ignoring whether the so called extensive kitchen actually works and used a nominal payload per berth, then possibly when a manufacturer saw that their product was basically described as 'unsafe for use' then they might get their acts together and produce things that do work. Of course it is possible that the designers are 'born again nudists' and do not see any necessity to carry any clothes.
Based on my 30 plus years of caravanning and motorhoming with family. and without, I would easily recommend that a 2 berth van has a minimum payload of 100 kg per berth, a 4 berth 75 kg per berth and a 6 berth similarly. Anyone who says that kids are smaller has absolutely no idea of the amount of clobber a child requires. These weights should exclude 90 kg for awnings gas bottles etc.
Now show me the number of vans that meet that criteria that are currently available.?
Sorry for the outburst, but the frustration boiled up. Many caravanners try to justify their overload by stating they are only travelling a few miles to the site. No, they know full well they are overloaded but deliberately choose to sidestep it.