I haven’t seen anyone post this yet, I don’t think. But small wooden chocolate boxes with a hinge like lid (like from LA Burdick) fit a Pi (Running volumio!) with a Hifiberry DAC perfectly. Just drill a few holes for the input and output. And then also you have chocolate while you make it!
Less healthy, perhaps, but wooden cigar boxes can make very nice cases. An aluminium cooking foil lining helps with RFI etc