The last rating agency to classify Greece as "A", i.e. barely still investment grade, is Moodys. If Moodys were to downgrade Greek state bonds to less than the simple "A", then Greece state bonds are no longer investment grade.
If Greek state bonds are no longer investment grade bonds, then no bank within the ECB can use them as reserves for the ECB minimum capital requirements. Greek banks bought around 30% of the last auction.
Hence: the classic rating agencies are at it again. In this case, if Moodys downgrades the rating - which is rightfully deserved - then the Greek banking system is defacto broke: they will have to sell or otherwise dispose of their Greek government bonds in order to acquire alternative assets to meet their reserve requirements. This would drive those bond prices heavily downwards and only the first sellers could come close to meeting their reserve requirements.
The classic rating agencies, as usual, remain backwards-looking and fail to consider the future: it's how they operate.
I fear that no matter how much lipstick you apply, we're still looking at PIGS.
The PIGS - Portugal, Italy/Ireland, Greece and Spain - are going to remain what they are: countries that are broke, but haven't realized it yet. Collectively, they're looking in confusion at their just-rejected credit cards and are wondering what could have possibly gone wrong.
The financial crisis of the last two years was solved by governments bailing out the financial system. The problem now is that these governments have to finance that spending.
At the end of the day, regardless of how you want to spin this, it always boils down to the payer of final recourse, the one who always, always pays the bills for errors, gregarious and otherwise, who always pays the bills for political bribery of voters to get elected, who always pays for failed policies and the pipe-dreams of political ideologues.
The taxpayer pays.
As Margaret Thatcher once put it: The problem with socialism is that at some point you run out of other people's money.
I'd update that to this: The problem with government spending is that at some point they run out of taxpayer's money.