as a GCloud user I've never seen any mention of IPv6. That's the main reason i've not bothered trying to get on the ipv6 bandwagon. I don't want to strugle through it if my hosting provider doesn't even support it.
CloudSQL instances support ipv6,[1] and appengine apps can receive ipv6 traffic, but only suggestion regarding delay in getting ipv6 to users was hardware limitations.[2] I wanted to know why op thinks this is only for external customers.
cool, thanks for the extra details. maybe they are using ipv6 for a portion of the internal infrastructure and the OP extrapolated that to mean they use it everywhere internally.