For those who may care, I was able to add a IPv6 glue record (DNS nameserver record) for a .COM domain registered with Network Solutions today.
First I went into their web-based configuration tool. On the page where you enter IP addresses for name servers, there's this message:
Advanced Users: To specify your IPv6 name server address (IPv6 glue record),
e-mail us the domain name, the host name of the name server(s), and their
IPv6 address(es).
So, I emailed them, at IPv6Req (-at-) networksolutions (-dot-) com, yesterday evening and they added the glue the next morning. This is verified with whois ns.drydog.com:
Server Name: NS.DRYDOG.COM
IP Address: 2001:470:C:2ED:20E:CFF:FE68:E4CC
IP Address: 66.27.60.10
Registrar: NETWORK SOLUTIONS, LLC.
Whois Server: whois.networksolutions.com
Also, as many of you probably already know, the top-level hints file at
http://ftp://RS.INTERNIC.NET/domain/named.root (version 2008020400 has AAA glue records for A.ROOT-SERVERS.NEt and F, H, J, K, and M. E.g.,
M.ROOT-SERVERS.NET. 3600000 AAAA 2001:dc3::35