Pictured here is a Musketier Radkutsche because it's one you could buy as a consumer, everything else with this config or similar - i.e. space in the back - is mostly those last mile logistic cycles and you can only really get them on a B2B contract.
This here fits an euro pallette in the back and has about ~200kg give or take maximum cargo load given a rider on the heavier side. pricepoint is ~6000€ upwards on account of they hand make this in the south of germany because seemingly nobody wants to do a factory for cargo bikes.
Over the similar in idea longtail cargo bikes that are loads more common this has the upside of giving you a flat, stable base to work from so you can throw on a big box or a café or whatever, like this:
These are pretty popular among uncs around here