I know it might not be exactly what you’re looking for, nor even remotely close, but a friend bought a 20 foot shipping container (AKA Sea Can) and didn’t spend much at all to install a regular (but very tiny) S & B type kitchen, insulate it, wire & plumb it, then had it installed on some concrete pads normally used as footings for a mobile home.
It’s absolutely rodent & vandal-proof and very comfortable.
The people he bought it from cut the back end off and installed a second set of barn doors. They also added two more sets of barn doors one on each side. The doors cover all the doors and windows when closed.