I get the idea-much smaller than the little busking/practise amps-even they would be incongruous hanging from the waist. Given that a redundant tranny or more modern portable radio/listening device might be already set up for a 2" spkr why not "shout out" [as these young people say] in "parts wanted" for something cool
or that can be silvered/blackened. Based on the pringle notion I presume we are in the 6x3" range or thereabouts. As an example my Roberts Radio R862 10 band job is 5x3x1" and black plastic [but in constant use]. I'm sure there'a chance someone here will have something knocking about
Dave W