I would definitely check out all the thrift stores, where you can often find unusual-looking electronics. You can spray-paint them white and put them onto any sort of rolling cart (or if you can't find a cart, put wheels on a table/podium). Most people don't know what it should look like anyway, so anything with wires and buttons/dials should work.
If you can find a thrift store that sells used electrical and plumbing parts, you can add more parts to complicate your machine, too.
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Veronica Brush
CO
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