I found an interesting article about GCC currency union delay here . It states that Oman can unilateraly opt out, and that other five nations amy extend official 2010 deadline for GCC currency adoption.

This is interesting as there was some talk that the new currency (supposedly named dinar) would be used to invoice dollar, which could take away some of the US exorbitant priviledge. I do believe that fewer currencies would serve the world better (dollar, euro, asian, dinar and possibly few satellite ones).