Based on the win ratio of teams like South Africa, Australia and New Zealand over all of the world. I'd have to say and Im very sure it'll be a safe bet that the southren hemisphere would win a lot and convincingly. Sure the north would come out all guns blazing but so will the south and the south would assemble the greatest side probably ever seen in modern day rugby, even the bench would be a sight to behold.
Oh dare I forget the other rugby nations such as Tonga, Samoa, Fiji and Argentina whom have many great rugby players themselves. I dont think it'll be an ultimate test unless of course the northren hemisphere team stack their team with some southren hemisphere players, I dont mean any disrespect to the fine current players of the northren hemisphere so please dont get that twisted but heres an example of what I mean..Last year the All Blacks toured the north and beat a lot of the northren hemispheres finest rugby teams and were only beaten by a Springbok dominated Barbarian side, maybe fight fire with fire would be the norths only chance and what does that say in the end??..