Their most visible effort at cooperation in commerce is OPEC. OPEC’s only success was in the about 40 years ago and that was mainly a political action and had nothing to do with commerce.
OPEC’s members are famous for cheating on their production quotas. Sure the oil producing countries are rich but when you look at the non-oil producing states they are backward poverty stricken cesspools of crime, violence and ignorance none of which are conducive to commerce.
Even the rich Arab states are hardly a hot bed of commerce. Out side of the royal families there is a tiny middle class and the rest are typically living in poverty or as they have for thousands of years as nomadic sheep herders.
Going to their own currency is a gutsy move to essentially use a hard asset (oil and gold) backed currency. It's a risky move as it delinks them from industrialized economies, namely the US. I think it will have some initial success but will ultimately not serve their best interests as the currency will fluctuate much more closely to corresponding commodity prices.