Substituting MAC for IP address is exactly what ZeroTier does. MACs can't be spoofed, though nodes can be designated as bridges and that allows them to impersonate MACs.
There's still the issue of authenticating IPv4 IPs though, which are too small to embed anything useful into. ZeroTier has a certificate system for that but it requires the use of the rules engine to enable it.
There's still the issue of authenticating IPv4 IPs though, which are too small to embed anything useful into. ZeroTier has a certificate system for that but it requires the use of the rules engine to enable it.