Simplestream mirror for custom images

I saw this thread and wanted to bring it up again - Simplestreams mirror for custom images

My use case for the mirror is to have a place where my CICD pipeline can dump custom images. Since MAAS stores custom images as a binary blob in the postgres DB (very bad), I would prefer not to upload them to MAAS.

Has anyone done anything similar or can someone point me to some docs that can help me setup a mirror? Thanks