To build a working case.. I first started with MiSTer – Case Universal v5.2 by NegSol on Thingiverse as the base.
This case design looks like it caters to a straight SDRAM pin layout (better SDRAM speed and reliability) and has enough room for a 25mm Noctua NF-A8 80mm type fan.
Here’s the first go at it.. needs to be a bit taller or the SDRAM won’t fit. Otherwise works great. The fan is powered off the unused GPIO1 pins 11/12 (+5V, GND).
19 Jan 2020 Update – see the white model I’ve printed which is 20mm taller to allow a better fit for RAM, and also the screws don’t interfere with the header pins.