It seems that M.2 SSD duplicators like SSD M.2 PCIe Dock & Duplicator are very interesting product option to add
We’ve got the SM2DUPE11 for handling not only M.2 drives of both SATA and NVMe, but, 2.5" and 3.5" SATA drives.
Now we just need a big chunky boy that adds in SAS, U.2, and I guess legacy IDE support.