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!