NYCEWheels is incorrectly calling these Brompton Case for Travel,
making people think it's made by Brompton. It's made by a luggage
company called B&W. Not sure if they targeted the Brompton market
on purpose or it just so happens the dimensions work out for B owners.

Amazon.com : B&W Folding Bike Box Clapton Box fits Brompton bikes : Bike Cargo Boxes : Sports & Outdoors

Here is my own semi hard sided suitcase/luggage for my B:
Brompton folding bike; ready for check-in by 1nterceptor, on Flickr