This is a trunk setup that I did including the false floor painted to match and the Air install was done about a year before. The cover for the Airpod was also painted to match.
The box is made of MDF and fiberglass.
The next is a little different. It is a box made to look like a race fuel cell. It was painted silver and airbrushed tig welds and then cleared in satin. It even has a real fuel cap and the speaker leads come out where the braided lines would go.
This is my own personnel setup. I used a vintage style suitcase and painted the textured fabric look over the brown leather using a cheesecloth. Then I made some decals out of postcards that we got when we were in Hawaii. A box is build it side the suitcase using MDF.