M2 Slot on any NK5.0 builds?

Been looking at the motherboards in the guide here, it doesn’t seem like any of the boards have an on board M.2 slot for NVMe. I am planning a 10gbE NAS build in an ATX case, and would like NVMe for caching for increased speed. Already have an HBA and a 10gbE NIC but wouldn’t mind having either of those already onboard. Any suggestions for an affordable build with an M2 slot? I would also prefer Xeon processors so I can use ECC ram because I may want to use ZFS.

I mean, you’d probably want 8th gen+, or something that can run x8/x8 which isn’t common except in some SLI mobo’s