Lutz,
Fully agree with you regarding TOTY. The groupings are based on vehicle type, whereas we as caravanners are more interested in the weight any particular vehicle can pull. If I have a van of a certain MTPLM, then I want to know what can pull it, not having to search all the sections to find out kerbweights etc. They also only use the top of the range models, which have gizmos, and prices, that most people never bother with. Some manufacturers have abandoned participating in it, as they feel it is more trouble than it is worth, especially if they get a poor write up.
The website 'Whattowcar.com' is probably the nearest thing we currently have to anything that will allow you to look at various vehicle/van combinations. It isn't perfect, because for starters it tells you nothing regarding fuel consumption. Yes, I know a Jaguar XJ8 will pull anything, but neither will it ever pass a petrol atation, so on practical terms is not that good.