I can believe you don't have any problems talking to the database over IPv6.Linode VMs are now native IPv6 enabled and it works good.Before that time we had to use a 6in4 broker to get IPv6 working on a Linode VM.
This may be a good place to refer to the nice people at HE [he.net](not affliated in any way) for people that want to learn about and do more with IPv6.
The free hands-on certification [he.net] is excellent and fun to do.If your provider lacks native IPv6 support, their free tunnelbroker [tunnelbroker.net] is a good help.The 6in4 tunnel adds latency but it's good enough to get started with.
Actually, when we yanked out the old A records, the only thing that didn't quite work was MySQL as it doesn't listen on IPv6 by default. That required one line in its config file:
bind-address = ::
Which set it to bind IPv6 only. I wanted to post the netstat output, but it seems it has too many colons and the lameass filter won't let it through.