Lordofwinter and I played a 2v2 game with 2 linked arena recently and it played pretty well. The arena looks pretty big at first when you set them side by side but it worked out.
My partner and I did a dual necro strategy while Lord and his partner did a Priestess/Anvil Throne Warlord strategy. We took pictures of the games progression and if you ask Lord, im sure he would post them.