but I don't see what you are proposing doing anything to address the underlying problem -- The crude owners do not wish to sell fixed price today for delivery down the road.  They want the down-the-road price and they want it to be higher, specifically as high as possible on the day of lifting and no less.  Pre-selling fixed price exposes the decider to questions on the lines of:

You sold 100 million bbls at $60/bbl?  The market is now $100.  We'd like you to go renege on the deal -- we'll get the Indians to prevent an invasion and sell it to them at $90 instead.  Why not.  It worked for the Venz, the Columbian, the Mexicans ....

Oilco/sovereign  management at all levels have no wish to have any system that makes them personally accountable for setting prices.  Their pay is too low to stomach the abuse that follows getting it wrong and their pay does not go up if they get it right. It's a no win equation.  Which is precisely why sovereigns and Oilco types love to do sales at Platts hi + X with a narrow set of dates or purchases at Low - X.  They know the customer will have to bash/ramp Platts on those dates since the material is only worth mean.  They are tacitly complicit in the manipulation that they then turn around and decry.  Only in Lake Wobegon is everyone child above average.

I also rather doubt the Chinese will be too excited to pre-pay in full for future delivery to an Iranian government that is slowly but surely pissing off the populace.  I figure they've got 10 yrs max before there is another revolution.  Iraq won't even have a government in a year.  More likely to be 2 or 3.  The rest of OPEC could not care less about cash up front.  They have plenty of cash of their own.  Buying the oil in the ground at the usual discount (equity ownership in the fields themselves) hoping to keep control using the same techniques the west has been pioneering in shitholes like Angola or Nigeria might work for CNOOC.  But handing over cash with just a promise????  You better get paid up front for your work is all I'd suggest.

As for labeling it "asset based" when in the end the selling party is still only obligated by a promise vs. labeling it "debt based" strikes me as sophistry (though I wishI could come up with a less loaded word.  I believe you to be sincere).