If Greek Banks Fail?

I was thinking tonight about one question: What if Greek banks fail because they are not propped up by the Euro?

If they were a part of a "too big to fail" banking system one or more countries could fall during this process when a too big to fail banking system goes down.

So, I think liquidity will be necessary to not only keep Greek Banks afloat but also to keep this "Too big to fail" scenario from Gutting European Banks in General and starting to bring down whole nations.

I don't personally know enough about the Greek or European Banking systems but just off the top of my head this could be a real worry down the road a little if they resemble at all American Banking systems.