I hope you're right. Because if the Euro succeeds, all those US Dollars currently being used as "the world's default currency" will make their way home. The US economy could use a little stimulus, but not THAT much!
I'm a little concerned that should the Euro really become the accepted currency of all 12 of these nations, we're going to have way too many dollars floating around the US economy.
and I'm a bit more concerned that almost no one else seems to be talking about this part of the story.
I suspect this isn't much of a problem. Dollars owned by foreigners are in the banking system, often kept in New York banks. For example, I've read that payments to the Saudis for their oil are paid by our oil companies to Saudi accounts in New York, so all those billions just stay here, much of the time. The only problem is with dollars that exist, but aren't circulating, such as suitcase money used in the drug trade. If that ever gets totally laundered and enters the legitimate system, there could be a flood of it. But then again, perhaps most of that is in foreign banks -- which in turn maintain large deposits in New York banks too. In other words, don't worry. The money is already here, one way or another.