What they are looking for is a new RESERVE currency, NOT a single currency. China, Russia and India have very large amounts of US$ in reserve, and the US$ volatility along with spiralling US debt is causing them a lot of worries.
The problem is that if they start switching to another 'new' currency, gold, pork bellies or anything else as a reserve, they will devalue the US$ and thereby their US$ holdings. It's a bit of a catch 22 situation.