Hey, thanks alot for this idea!

I made a rapid - rapid prototype of wood and carboard to test this and it works wonderfully.

I haven't measured the sound level yet, but it is now at a level that the high frequency noise from the power supply fans are getting more annoying, with chip temperature at around 90 deg Celcius.

Have you considered turning around one of the boards so that the heatsinks both face inwards? I see a 10% higher temperature on the board with the heatsink facing outwards.