My problem is that I usually have a second piece of luggage, a tad wider than 50cm, and I need to accommodate that width somehow - no, I do not want to place the suitcase on the side and cope with the center of mass wobbling. This takes out too narrow trailers such as Travoy. In terms of trailer length, the Vincita bag (B-bag as well?) puts it at 60cm for the folded trailer.
The Andersen Shopper looks good if not very good. After all, I often might put a suitcase on a luggage cart. However, the devil is in the details. Andersen give no dimensions and have no dealer in the US. Even if I were somewhere where they have a dealer, it would take time for them to get an item from Andersen and there might be an issue if I did not like it. This indicates though that I should look at luggage carts.
I looked some more on the Andersen. My reason for suggesting the Royal shopper plus (at 58 cm wide) is you mentioning the 50cm plus luggage.
Then I realised that if you buy a narrower Andersen trailer with a bag you no longer need to worry about atatching your present piece of luggage to the trailer.
I have been looking at the Tura shopper. It has 29cm wheels, mudgards (I hope they are detatchable) and is 55 cm wide. The folded Brompton is 56,5 cm wide so Brompton would protect the frame innside the V bag (with some padding in between.
Trolly part minus bag is 127 cm tall. Take off the wheels and it is approx 13 cm shorter, that is 114 cm tall. Looks to me like it is telescoping down to half size so that is 57 cm tall, folded B is 585 so Brompton should protect it innside the bag.
Frame with Aqua (bag is 56 l capacity and can be carryed as a backpack when off the frame) is 5,1 kilo. I think that is wery light.
Especially becouse of the mudgards it should be possible to stuff something (approx 16 cm tall) at the bottom of the frame and roll the B on the frame and carry the bag as backpack. Not sure you can put both B and bag on the frame. Weightwise yes but maybe not practical.
On the regular shopper frame (164-000-80 w 29cm wheels, 50 cm wide, 111 cm tall) it may be easyer to carry the B becouse it has got two "spines" on the frame, not one as the
Weight toolly with aqua bag 4,5 kg so lighter than the Tura but Tura is 5 cm wider so a tiny bit more stable when riding. I think this is lighter than any suitcase & trailer combo you can find elswhere.
You can get an Ortlieb bag with both frames, capacity 49 litres so smaller than the two others but same weight as the aqua bag. Ortlieb has no backpack option.
http://www.andersen-shopper.de/files...6_2017_web.pdf
I`ll see if I can take some pictures of the Shopper I gave to my friend tomorrow.