There's GTS Negotiation. I'm not quite sure of how it works, but apparently you choose three Pokemon and get paired up with someone randomly across the world that has also chosen 3 Pokemon. You both get to look at the stats and stuff, and trade if you wish. The possibility of getting a Tornadus is probably slim, though. And because the event Pokemon aren't out, your chances are even slimmer.
I can check this myself if necessary, but does anyone know if Pokerus is kept with Pokemon that have been Shifted from 4th Gen to 5th gen?