Hi.
I've written a patch that uses GeoIP IPv6 database. I've made some quick tests (connect with my external IPv4 and my public IPv6) and it seems this patch works.
Usage is simple. If you specify the IPv6 database, it will use it for IPv6 and IPv4 addresses (same variables).
If you specify the IPv4 database, it will be used only for IPv4.
This patch is based on Nginx 1.0.4.
Best regards.