I couldnt find any official or community made box for the Pine64 (a 64bit single board computer from 2016+) that also supported the Audio DAC POT (HAT in RPi lingo). Likely because the silly (IMO!) design of the POT means you cannot screw the box in from both sides! Not to worry, I put in a couple of clips and anchored the box around the RCA connectors (put that side in first), its more than secure enough.
Has lots of passive cooling potential thanks to open grille and snazzy PINE64 embossed logo and wording though I have heatsinks on my Pine64. You will also see in the images I left space for a power connector which you can solder into the pins on top of the Audio DAC POT to power the whole unit without using the unreliable Micro USB connector.
Picture is PLA+ painted black with fake weathering to look like a metal box. Due to the thin grille its quite flexibe on my PLA print, expect it to be more rigid with something like ABS or PC.
Bonus STL of my Fusion 360 mockup of the Pine64 board.