Also see
https://forum.45homelab.com/t/modding-upgrading-backblaze-storage-pod-2-0/737
if you have not.
You can contact 45Drives and they will give you a quote on a bare Q30.
It seems like most of the design work has been done and it’s really more a matter of acquiring the boards the drive connectors mount to and doing all the cable management to wire those in. Tedious, but probably less expensive than a bare Q30. I think the HL folks have been pretty adamant that a HL30 is not on the radar any time soon. I shouldn’t think ‘direct wired’ with actual wires would be less reliable than the direct wired backplanes.