I wish there were a possability to choose in what country the payment systems should be valid for. For example, many times you may not want to offer invoice for foreign customers, since it will be harder to collect the money if customers don´t pay (the invoice company in Sweden doesn´t approve any foreign customers, and it would be much better if this system was not shown for the foreign customers in the webshop). And in some payment systems the cost to exchange the currency is way too high and therefor you don´t want to offer this payment system for foreigners..

I was thinking the exact same thing while setting up my payment options. I accept checks from domestic customers, but not from international customers. Is there any way to "turn off" payment options based on location? (I know I can set this up via user types, but I prefer not to have 2 different customer types.)
 
Any thoughts on this?

I've recommended to ViArt already, that anything that has a 'Site' / 'UserType' delegation, should also have a 'Countries/States' delegation as well.

Yes, that would be very helpful.