The Germans would have to be damn fools to go back to the costs and hassles of cross-currency activity.  If nothing else, their food prices would rise as there is no chance in hell - AFAIK - that the Danes and Poles are going to give-up the Euro, implying the German consumer would end-up paying for the costs of cross-currency transactions for both the importing and exporting companies.  

Politically, European stability, by that I mean "not shooting each other," stems from the Germany/French Post WW2 alliance.  Germany withdrawing from the Euro would certainly cause 'tensions' in that alliance and, to an extent I cannot comment on, put that alliance in doubt.  

Merkel & her band like to pretend they are oh so fiscally responsible but it's been demonstrated elsewhere in this diary that's a lot of malarkey.

All of which leads me to suspect Merkel & Co. are playing some kind of Game.  What Game and Who it is directed to/at are questions I defer to those who have greater insight.