There is no need for a plan B. The Greek government is still on track for its plan A:
Agree to any negotiation but never finalize anything. Start making silly claims (ww2 payments) yourself. In the mean time all of their personal assets are long safe. When finally nobody sends money to Greece anymore they'll go bankrupt.
Then tey'll blame it on everybody but thelselves.

Why they don't take on the chucrch ?
Why they don't take on the superwealthy Greek ?
Answer is easy, politicians from any party are very closely tied to both of those parties = corruption.