Quote from Megadog »Mirrodin was populated with species from other planes, was it not? Considering there are only two other planes with Vedalken, it's not a stretch to assume the Vedalken of Mirrodin were originally from Alara, much the way the Loxodon appear to have come from Ranvica.
Actually it IS a stretch to assume it since all the inhabitants of Mirrodin were sent back to the world they came from.* We get a glimpse of that world at the end of Fifth Dawn, with Leonin, Vedalken, Goblins, and Humans all meeting for a summit by the sea.
That scene would have been impossible if it had been Alara because none of the details match.
*Horrible Scars of Mirrodin retconning not withstanding.