[rich_sasha]

They could presumably strike some deal, if there is political will on both sides.

UK and Scandinavia got to opt out of the Euro, for example.

[smhg]

You mean Sweden and Denmark, not Scandinavia. And both have different ideas about joining the Eurozone. Norway isn't part of the EU. Finland is using the Euro.

[diplocorp]

Finland is Nordic but not Scandinavia. Because Norway is not an EU member, discussing a euro opt out doesn't make sense. Thus, OP is accurate in stating that Scandinavia got a Euro opt-out.

[Hamuko]

Sweden and Denmark are the only Scandinavian countries in the EU.