You would have all of the domains point to the same IP address... so there would be only one version of the pages.
Of course someone could go to the other version of the site if they wanted to, but I don't see why that is a problem.
You would default to the main country and then allow them to change it.
You would need to probably find another service to do the exchange rate as well if you didn't have separate fields for price in each currency in the products table that you maintain manually.