Anyone with fully IPv6 networks out there?

I am thinking futuristically in asking this question but I want to know if there are any full IPv6 networks in existence yet.

With the exhaustion recently of RIPE's last remaining IPv4 block allocation, I am wondering if any of you out there have begun or interacted with a network that is entirely IPv6 native yet. Meaning, there is absolutely, 100%, zero IPv4 space allocated within the network, either as a public IP space or private IP space.

If that is the case, then drilling down into what a fully-native IPv6 network looks like:

• What does your routing internally look like?
• What does your public routing infrastructure look like?
• What were some design considerations and best practices that you used for:
  • IP address space allocations
  • Point-to-point routed links
  • VPN tunnels, if any exist?
• What did your transition look like from IPv4 to IPv6? What are some challenges and objectives you had to overcome?
• What was the total project cost? How much did you have to dedicate in equipment upgrades, man hours, outages, etc.?

Part of this is that I am kind of dreaming out loud here, but I also know that eventually one day this shift will have to happen and I would rather start thinking about it now rather than when it absolutely must happen.