I decided to build my own power efficient NAS using a Raspberry Pi 5 and two 3.5" HDDs, and some hats.

The below components is what im using

• Raspberry Pi 5 8 GB
• Geekworm X1009 Sata controller
• Geekworm X1001 NVME controller
• HatBRICK! Commander PCIe-switch (2 PCIe)
• Kingston NV2 M.2 NVMe Gen 4 250GB

To make everything work, you need M3 standoffs (yup, M3, not M2.5) which I discovered after the design that is the wrong dimension. I solved it by simply drilling out the holes in the different boards to 3 mm. Works perfect. You also need M3 threaded inserts in order to tighten the screws used.

The top plate has cutout for a 80mm fan, but I havent got to try that out yet.

The most difficult part of the assembly is to get the threaded inserts level, but once thats done, its just a matter of screwing it all together.

There is no back plate available as of right now, but that is on my to-do list and to add that here as well.

The pictures of my prints have two faults. 

1. The sides raised for some reasons on my print bed, but thats an error on my end, not with the model itself.
2. The screws used to fasten the HDDs make the sides bend a bit, but I added a cutout in the HDD bay so that shouldnt be an issue anymore if you decide to print the case.