Isn't it fundamental that you can't have a single currency without (at least) a federal government able to raise taxes and redistribute wealth from rich parts of the union to poor ones?
This is how and why the UK works (apart from the federal bit). Scotland, Wales, Northern Ireland and the poorer parts of England are subsidized by London and the South-East. That's why the pound isn't seen as a problem.
IMO if Germany doesn't want to fund Europe's poorer states, the solution is for Germany rather than Greece to leave the EU!