Nice. Got a link for this one?
It was oddly snuck into the private DNS announcement
http://aws.amazon.com/blogs/aws/route-53-update-private-dns-...
"You can create generic "white label" name servers such as ns1.example.com and ns2.example.com, use them in your delegation set, and point them to your actual Route 53 name servers."
However, making your DNS servers to be responsible for serving their own DNS is a bit of an extra complexity and risk that no customer will ever care about..