Google released their own VR experience for HTC Vive via Steam, where you can visit various different locations with the help of Google Earth data: Google AR & VR | Home
We have been toying around with the same idea at Umbra since last year, as we have been developing our 3D graphics optimization technology further. Check out our prototype demo made with Unity:
Just wanted to say we are releasing this technology first as a Unity plugin early next year, but are also looking for projects to our closed beta as we speak. Yes, this is a shameless ad but as we have a lot of Unity devs asking about this quite often, I feel like this might be relevant to some of you, especially if the amount of data is the issue on your project.