So, has anyone considered the humble suitcase?

[Commander Truestar]

The baggies material, assuming flexible plastic, should be able to adjust.
And, if it's space spec, it should be able to deal with a wide temperature differential.
Aluminum, I donno.

Well,
To address both @Condottiere and @Enoki,
@Enoki - these are designed to "protect" when in transit, which may include being in void.
"But" to be packed and unpacked in shirtsleeve environments.
The user packs the "deflatable" section in an atmosphere, seals it and then the in-built vacuum deflates it to create "Room for more"
Yes, the case is heavier but, as is recognized, it is anti-grav
The bag is then opened in an atmosphere at the destination

@Condottiere
The "sections" of the case which can be deflated are internal to the case.
Because of that, they are within a sealed and space-resistant material, like being inside the hard shell of a samsonite suitcase.