I think what you suggest is not a scenario but is progressing quietly behind the scene if shits hit the wall. As I'm typing now, Greece gov may already finish printing the new drachma and Germany/France will keep procrastinate over their differences while each of them has prepared for the worst.
Smart money in Greece is tracing it's way out of the country to Swiss bank because the rich n powerful know what happen next. Default and switch back to drachma. 228 bil euro had been transferred out of the country recently to Swiss bank alone and who know how much has been smuggled out so far???
Default, write off, forgiven, structural ........ What ever jargon labeling it. It's happening now IMO.
