Brazil and Argentina DO in fact want to be big just as you describe. But the big stars of economic growth are not on board (yet): Perú, Chile, Colombia. This movement is rather the political "anti-imperialista" club of Ahmadinejad's bedfellows: Venezuela, Bolivia, Ecuador (Nicaragua and Cuba are not copying the idea, because Nicaragua is small, and Cuba doesn't want to be in Ahmadinejad's club at all, despite it's being the craddle of anti-imperialism). Brazil and Argentina see an ultra weak Obama administration in foreign policy. And the emboldening of peripheral countries seems a world-wide phenomenon.
4 UN peacekeepers injured in Sinai and taken to hospital in south Israel (Haaretz)