This appears to be correct, but is however still lacking in functionality, because I can not register BOTH an IPv4 *and* an IPv6 address to one nameserver with the registry.
As far as I know, this should be possible. Could you look into this?
I really would like IPv6 nameserver glue for my .com domains too. http://www.sixxs.net/faq/dns/?faq=ipv6glue currently still lists Dynadot as a registrar unable to provide IPv6 glue for domains.
For this to be properly enabled, Register a domain name server should take both an IPv4 and an IPv6 address for a single nameserver entry (e.g. ns1.example.com), for the domains that you can provide IPv6 glue for. (e.g. .com, .net, .org)