Hi guys, I'm here to put this thread to bed. As 'the guy' who officially monitors suggestions and then pushes them to the devs for new builds, you can consider this the absolute final answer to the topic at hand.
Short version: For all intents and purposes, this will never be a feature that makes it into Toribash as we know it.
Long version: It has been tried and tested (some of you may see screenshots and the like of that time) and playtesting ruled that 2v2 was a) not very fun and b) made physics wonky, namely things were a lot slower than they were supposed to be. It would currently be a lot easier to create a new engine that supports 32 vs. 32 players than to force 2 vs. 2 into an engine that's ~10 years old and the product of a one man development team. It's not feasible. To reiterate: this has nothing to do with hardware, more the limitations of the game engine itself.
And so we're done. Any other suggestions that are of the nature of increasing player count should be closed & shown this post because unless we start working on Toribash 2 (full disclosure: we're not) you wont be seeing an engine overhaul any time in the near future. As long as I'm around and doing this sort of thing I'll be the first to let you know, though.