Countries are hard coded in a PHP file; I (or even IPS) don't store them in a table:
/**
* GeoLocation
*/
class _GeoLocation
{
/**
* @brief Country Code List
*/
public static $countries = array(
'AF', // Afghanistan
'AX', // Ã…land Islands
'AL', // Albania
'DZ', // Algeria
'AS', // American Samoa
'AD', // Andorra
'AO', // Angola
'AI', // Anguilla
...
'YE', // Yemen
'ZM', // Zambia
'ZW', // Zimbabwe
);
We can certainly add items to that array but that would be definitively made as a custom job as I won't change the main app. Also, I'm only saying that by taking a look in that file... I would need to test to see if it would work.
Send a message if you want to make a try as a custom job.