public ipv6 dns

Живые
Hurricane Electric

• ordns.he.net: 2001:470:20::2 (globally anycasted in 11 countries)

ISC

• f.6to4-servers.net: 2001:4F8:0:2::14

И еще куча дохлых
http://www.getipv6.info/index.php/DNS_and_Naming_Issues#Recursive_DNS_server