Yeah I've read that the first Iraq war was actually triggered just as much by Iraq's decision to request oil payments in some other currency (not dollar), as by the events in Kuwait. And I've read more comments to the extent that they US is prepared to do almost anything to keep the dollar as the international currency.
Russia could temporarily switch to Euro for the gas/oil payments from Europe; I can't see why that would be a problem; I mean the EU is the biggest trading partner for Russia other than CIS, isn't it? So why not keep some stores of Euro along with dollar and gold?
Then if Russia wants to use roubles further on they could come to some kind of agreement with the EU. Not sure how stable the rouble is right now but why not?
But if Russia moved away from the dollar, that may be the end of a beautiful friendship....
But an internationally neutral currency would be the best. But that leaves the interesting question of who rules that currency and who rules those who rule the currency...? For example, neither the UN nor IMF is completely inbiased and have been accused of being dominated by a certain country/countries and their agendas.
I think the idea of a neutral currency might just be one of those nice ideas that are not possible to implement. The USA has the biggest army as well as (in the past) the biggest economy.... I wonder how much of a role that plays? Probably quite an important one!
If economy + army is part of the equation, then China's currency will take over sooner or later.