Hello,
To be honest I don't know of any non-server board with build-in IPMI/KVM.. Probably some board Vendor
can do that , I just don't know any..
As for ECC it is already supported for TR. Is again a decision of the board vendors(s) to support ECC or not.
I know only one TR board supporting ECC , this one :
ASRock > X399 Taichi
BR