One of the issues with real estate investing (since this is essentially what the Greek government is trying to do) is the mantra of "location, location, location!
The Greeks want to get top dollar for their land so they can pay off billions of Euros of crippling debt, but as a buyer, I'm going to want a reason to pay top dollar, and vacant farmland in Thessaly isn't going to cut it. I would be willing to put in a bid for the Acropolis, some great beachfront property on the island of Mykonos (oh hell, the entire island) and maybe Arcadia, so I can grow grapes to take on my picnics at the Acropolis. Most other buyers are going to be thinking along the same lines, so the Greeks could be paying off their debt by selling Mount Olympus and other high value properties, much like Monopoly players can mortgage properties to stay in the game.
What do you mean, the Reading Railroad. I distinctly said Mount Olympus!
Ownership comes with privileges, like being able to do things to increase the value of your possessions, transfer ownership to others (I sell the island of Mykonos to you so I can afford some more classical Greek temples on the mainland) and so on.
The other issue for the Greeks (besides their new landlords jacking up the rent or simply kicking them off the land) is the Greek Government is going to find the property owners are not just going to sit still to be milked by the Greek tax system. Anyone who goes into a land auction under these circumstances know they have the Greek government over a barrel, and can insist on clauses like having a 99 year tax holiday, only be subject to the laws and customs of the owner's home territory (this could be hilarious in the case of the Brexit, as British land owners impose British rules on their property rather than Greek or EU ones) and so on. The Greek government will also be either subtly or forcefully reminded that these people are rich and powerful in their own right, and certainly going to be more than willing to defend their own interests. Londoners who have encountered the retinues of wealthy Arabs from the Gulf States will certainly understand the sorts of behaviours I am talking about.
This could be played out as a comedy, but since the Greek government is essentially selling its Sovereignty it is really more of a tragedy. Simply defaulting on their bonds and being cut out of the international credit market will probably be equally painful, but have fewer deleterious effects on the average Greek citizen.