Hi there,
Thanks for the kind words.
I believe what you're after is this line of code new DropdownField('Country', 'Country', Geoip::getCountryDropDown(), self::findCountry()). It can be viewed in the source browser at:
http://open.silverstripe.com/browser/modules/ecommerce/trunk/code/EcommerceRole.php
Change your EcommerceRole.php in your site so that the 4th argument to the DropdownField self::findCountry() is removed. This should stop the country dropdown from populating a default country. If there are any other instances of the site where a country is defaulting, just do a search on all ecommerce php files for findCountry() or Geoip::visitor_country( in all files.
Originally this was in place so if you're a member, it used your member's country as the default in the dropdown. Otherwise, if you're not a member, or the country hasn't been set in your member preferences, it attempts to find what country you're from based on IP address.
Hope this helps!
Cheers,
Sean