Cyrille: "There remains another one: since Germany is determined to have a massive surplus, it needs to invest its savings abroad. Will it be all that happy to be facing a yearly depreciation of around 6-8% for the foreseeable future?"

That would certainly be a problem for existing investments in Euro-zone countries were Germany to leave the Euro-zone. But most of the depreciation would likely occur immediately, rendering EZ countries X-Germany attractive targets for new investment. And, while German investors may take an immediate hit on the value of its foreign assets, should  not  assets become more competitive and, thus, their net present value should increase to offset the immediate loss due to currency revaluation?  

I agree that, medium to long term, there are probably hard limits as to how high a new Deutchmark could go relative to other countries without Germany becoming uncompetitive in its core products. Although a lot of those losses could well be to relocated subsidiaries of German parents. But would that not start bringing the downside of globalization home to Germany and result in a hollowing out of German Industry?

"It is not necessary to have hope in order to persevere."