One final point I wish to make Marcus, and though no fault of your own, is a thought that has often been expressed by so many other members on here; no vacuum cleaner is perfect, and neither are the brand. Some come close on truths but largely at the end of the day, most are out to make money and can often be liberal with the actual truth.
With regard to testing new carpet pieces, I'm not entirely sure how that would work. Spira makes a very good point that top soil carpet would have to be removed first if new samples of existing carpet was to be used, but I would still expect infrequencies of data in terms of pick up. Lets not forget that though some brands are using different quality bristles in the brush rolls, only a few brands are also making changes to the actual sole plate and general design to allow more force of suction to occur.
Whilst I have said it all along that the EU energy labels have not been properly thought out, I don't think it is all that important to know if a vacuum cleaner should have a rating for pick on dust from carpets and hard floors. After all, how can one rate a vacuum cleaner usage on just floor use alone? If we are going to get pedantic, then surely there should be a test that conducts sealed suction instead as well as durability? These aspects would be a heck of a lot better for customers as well as, to some degree, contribute a much better rating to support eco concerns and long term maintenance.