The large pool of oil you describe is in the ground in a myriad of countries.  No big producer has huge tanks of unsold oil beyond what they need for operational flex. It's too much capital tied up and nowadays would just be a target for Osama (Saudis do sometimes rent in order to take market swings without screwing with the fields too much).

Reliance on the performance of oil nations, many of which are run by criminals is a no hoper.  Good luck.  Maybe you'll prove me wrong.

Markets where the countries already have strong rule of law and players have good credit/performance reputations are doing fine with traditional finance.  Aussie LNG is pre-sold to the Japanese such that financing (often from Japanese banks) is secured.  Seems to me that already matches your re-labeling exercise pretty closely.  The players divvy up the expected profits based on their own projections and a negotiation.