Currently, the value of the euro is a function of the strength of the economies within its zone. If it should break up, we will presumably see "euro" deposits become guilders, deutchsmarks, punts, lira, and so on - at which point, 1 "new deutschmark" will presumably rise against world currencies, while the new punt or the new escudo slides.
So, an arbitrage opportunity. A mustachian with cash in a "weak euro" country might consider joining the huge northward flow now exiting banks in Greece, Spain, and who knows where else. Moving into a non-euro country creates a foreign exchange risk, but in this scenario, 1 weak euro buys 1 strong euro. No breakup, you've still got your euro. On the other hand, a breakup could increase your buying power by 70% relative to a "stay home" scenario.
The question is, where to? It needs to be:
* A very well-capitalised bank with little exposure to, for example, empty and unsaleable Spanish apartments.
* A strong euro-zone economy.
* A bank happy to accept deposits from non-residents.
I'm interested in BCEE (Luxembourg), but there must be others... right?