to clarify about the Mädler luggage:
the foldable suitcase is called "aviatic" and was offered since the early 50ies and these types of foldable luggage is still in production, f.i. by Seeger in black leather.
There had been two versions available:
a 100 cm long versions for 4 men suits
a 137 cm long version for 10-12 women skirts
these had been available with a light stabilising framing as an extra for a surplus.
Attached are advertisements for the luggage from introduction in 1952, 1953 and 1963 to show the consistancy of the luggage type.
The advertisement slogans are
"the pinnacle of travel convenience - the new carbag"
"directly from the wardrobe into Mädlers carbag"
For those who obsess about exactly how their 356 left the factory!