Please accept my apolgies - I was mistaken. I was thinking of dnscurve.cz and extrapolated this to conclude that nic.cz was dnscurve-friendly. But we now know this is not the case. They do not view it as being worthy of adoption as a "standard". Sad.
Unless I misunderstand you, unfortunately this is not the case. A quick way to check if a domain supports authoritative DNSCurve service is to do e.g.
$ dig +short ns dnscurve.org
You'll see labels that begin with the magic string "uz5" followed by a Base-32 encoding of a Curve25519 public key.
Unless you meant something else?
I agree with your post though. I also use tinydns, but with CurveDNS for DNSCurve support in front. They just work!