Generally speaking, Apple allows the US carriers to have an "exclusive" on locked phones for a time after the release of a new model. Eventually (shouldn't be long now), Apple will start selling a factory-unlocked model (already available in many other countries, such as Canada).
In Canada, Apple currently sells iPhone 5 units factory unlocked starting at $699 (my preferred 32GB model is $799). Translating that into Krona would equal 101,624kr. (wow!) As you say, buying an unlocked iPhone 5 in Iceland appears to cost around $1,400 (US or Canadian, we're roughly at par).
If you could arrange with someone with a Canadian credit card to buy the iPhone 5 in Canada for you and ship it over, it would work with your carrier(s). But that's an awfully big IF.
Otherwise you'll just have to wait until Apple US opens up for unlocked iPhone 5 sales.