A word of warning: there was a supermarket selling food from various European foods (British, German and others) in Sosua and it closed about a year ago. But it was a big place and competing with more established supermarkets when selling every day items. If you did it on a smaller scale and also had an online sales and delivery operation as suggested by Belgiank, it might work well.
True, but there are very strong rumors that the Russian landlords did not renew the lease. On top of that, they made one huge mistake, in my humble opinion, which was to make everyday items ridiculously expensive. If I really want to buy marmite, f.e., I do not mind paying more then I would in England, as it is a luxury item. But if I have to pay a bottle of coke 65rds, while everywhere else at the time it was 50rds, that is something else.
If I were the OP, I would not sell everyday items, just Europeans, and possibly American items, at fair prices (taking into consideration the import costs, of course). And sell them nationwide, online. I would also try to find suppliers who are flexible. So if a customers comes to him, requesting a particular product, he can supply it, even if there is a waiting time involved.
One downside to all this, I think, and that is the huge investment it will require.
But I wish all the best to the OP, and will sure check him out, and probably order, if he gets it of the ground.
BelgianK