Hah, well there are national DEMs available, and land use datasets - you could generate a natural landscape minecraft map quite easily.

> Is this something that can be (has been?) incorporated into the likes of OpenStreetMap?

It's worth nothing that LINZ have been extremely helpful with things like licensing and funding to get core topographic data into the OSM set for New Zealand. See this page:

http://wiki.openstreetmap.org/wiki/LINZ