Political and fiscal union won't work as the financial transfers from Germany to the PIIGS are estimated at at least 200bn per year and Germany can't afford that.
The fiscal transfers required in the UK to Scotland, Wales and Northern Ireland cause a lot of resentment from the English, and this is a fraction of what will be required of Germany to the rest of the Eurozone.
Germany might be the richest country in Europe but is far from healthy economically where they are a socialist state who have borrowed heavily in the past, their dept to GDP level is 82%. They also have large pay as you go liabilities, with a Public Sector pension liability of over 4,000bn. Their banking sector is currently weak with much exposure to other EU countries and their banks.
Money flows in the EU are handled by a system called TARGET2, so where there is capital flight from Greece and Spanish and the money is deposited mainly in Switzerland and Germany, then Germany lends this money back to Spain so they do not have liquidity crisis. In February Germany had lent over 600bn to other central banks. The rate of growth is increasing as more and more capital is leaving Greece, Spain and Portugal, In February it was increasing at about 70bn a month, it is now estimated at 100bn a month. If this continues by the end of this year it will be between 1tn and 2tn. When the Eurozone music stops if the PIIGS central banks can't or won't pay back this money, you can imagine the effect it will have on Germany's economy.
Germany is not a indebted as the UK, but there are potentially ruinous things on the horizon.
To me an analogy on whether to go back to individual currencies quickly or slowly is: There is a very sick patient, the doctor comes in and says we can perform a major operation, you will be very, very ill and weak for between 2 to 9 months before you start recovering. The alternative is that we can treat you will a regular course of drugs for the next 10 years, you will be weak and ill but alive, you will get worse and worse during this time and at some point in the 10 years things will get so bad you will have to have the major operation, but because you are so much weaker at this point, recovery will take much much longer.
All of the EU politician are aiming for the latter, for re-election, career, expenses and pension purposes. I personally can't see any other scenarios.
Matt in the DT, summed up the EU banking fund suggestion perfectly:
http://www.telegraph.co.uk/news/matt/