Well, location will be fixed to an extent with IPv6. All you need to do is contact the ISP that owns the appropriate /48 or whatever they were given, ask them the address of the customer with said /64 and there you go. Of course, this is the same thing they should already be doing with v4, carrier-grade NAT is fairly uncommon for anything but mobile use except in Asian countries.

Still, you can't tie an IP address to a specific person or computer, v4 has NAT to contend with and privacy extensions with v6 (which Microsoft and Apple use by default, most Linux distributions do as well) - so regardless if you can get the physical location where that IPv4 address or IPv6 prefix is assigned it does you no good on determining who was actually behind that address (unsecured wifi or easy to crack passwords, malware, the list goes on).