There are a few people currently working on NAS boards based on the CM4. A few different approaches in terms of chipsets used and performance targets. I'm trying to track them in this GitHub issue [1] but a couple people have remained more or less anonymous as they don't want to attract attention too early. The single PCIe lane is the biggest limitation if you're looking for raw speed (350 MB/sec is kind of the upper…
(the Gumstix camera board is overkill for my needs)