[your24hourstore]

there is a mod that shows the flag of the country of the register, and you could make them select their country , although they could lie, but a flag is displayed in the postbit legacy area of the posts, you would then be able to double check them by grabbing their IP and checking it against the list using a site like this one

or this one you could even edit the php file that is in that mod to reflect the ip of the country in the postbit legacy also, but you will need a list of each and every Ip used by a country , or that is on your server.
it would be daunting here is a command line input command that will ping

Open Command Prompt and type:

 FOR /L %i IN (1,1,254) DO ping -n 1 192.168.0.%i | FIND /i "Reply">> c:\ipaddresses.txt

The "-n 1" is for only 1 ping packet to be sent to each computer.
Change 192.168.0 to match you own Network ID.
This will ping all IP addresses on the 192.168.0.0 network segment and create a text file called IPADDRESSES.TXT in C:\, where it will list only the IP addresses that gave a reply. this may work to do what I have said here but would have to be done every once in a while then added to the list IPADDRESSES.TXT