When an individual or a company defaults on payments they owe, their assets are sold off.
Greece should have to give large areas of land or whole islands to the banks and countries they owe money to.
This would solve the problem.
1. Greece would be free of debt.
2. The banks would hold large assets they could sell or develop, with the proviso the new landowners and developers must accept Greek and European Law in that order, but all profit would go the bank/country owed money.
3. The rest of the world would no longer worry about the state of their own economies getting in the mess Greece has got into.
This would also show Portugal, Ireland, etc, that they must get their houses in order or lose their own land.
By the way, have these countries said thank you to us (UK etc), the countries and peoples who have given them our own money while we endure our own hardship ( thanks in UK to Labour Party incompetence)?