The idea of central bank controlled cryptocoins has been around for a while. I fail to see that these coins pose any serious risk for the valuation of Bitcoin or precious metals and I don't think such a concept will be successful.
The reason for this is pretty simple: Even if such a coin is constructed under the umbrella of the IMF it still doesn't represent a real valuable asset, because it is subject to political influence. There are also many questions regarding its creation. For example how should the coin be mined - should every country mine its own stash or will there be fixed quotas allocated to each country? How would all countries of the IMF even be able to form a consensus?
An IMF coin will never constitute a real asset like gold or Bitcoin, because it's not functioning as a incorruptible natural resource. Instead an IMF coin would be some kind of "meta-fiat" used as backing for fiat.
ya.ya.yo!
I sincerely hope you're right, but the idea is that Imfcoin would be essentially no different from Bitcoin (or gold,for that matter), in order to build market confidence. It would be open to mining by anyone -- it's just that the IMF would have already mined more than half of the 21 million coins possible before announcing it. (Countries would be given coins from the IMF stash according to their GDP, foreign currency reserves, etc.)
Note that this would be no different from the gold-standard period. The elites enjoyed and praised the gold standard when they owned enough gold to keep the system stable while issuing paper to benefit themselves. (Initially, they would set the peg rates so countries would own more than enough imfcoins -- so they would be able to borrow and print lots of local currency to stimulate economies and to keep political discontent to a minimum.)
And I wouldn't be surprised if the elites would boost public faith in Imfcoin by making a couple of examples: some small, marginal country would come begging to borrow a few dozen imfcoins to tide itself over after a financial crisis, and the IMF would refuse unless the country implemented 'reforms' that made the pain even worse.
But you're correct that there's fundamental problem to the whole project. If a new 'gold' can be created at will, what good is this 'gold' that the elites are promoting? I'm worried, though that it might take a couple hundred years (a couple of boom-bust cycles of new international monetary arrangements) for the public to wake up to the problem.