Interesting build. I see a few things that could be changed to save you some dough. First off, you don't need a 1200w psu. That is way overkill. 850w should do it. For the memory, I would go with 2*8GB so that you can upgrade in the future. If you are running three monitors for gaming, then SLI is necessary, if not, don't waste your money. Although its a good board, the Sabertooth is overpriced, I suggest something cheaper, like the ASRock Extreme4. To finally get to your question, any case that has a side intake fan should help cool those cards in SLI.
Well, the PSU is on special it is only marginally more expensive than the 850. As for the RAM, im mainly going to use the computer for gaming, I think that 16 GB is already overkill, I was seriously considering just 8GB. As for the SLI, Ive seen how these cards run on 1920 by 1080, and Im the kind of guy who doesnt want his games going below 60fps, which for some reason the 680 is still not able to do with the latest games. That combined with the fact that I want to be ready for the next batch of next generation games (unreal 4 and such) and I probably will regret not getting the sli build when I had the chance. Oh as for the Sabertooth, I really didnt want to skimp out on the mb or proc thats why i went that route, dont want later to regret spending so much on all the extras and have a budget mobo dissapoint or fail.
Cant select that, im going pre built. Besides I will OC down the road, when the games start demanding it, just not yet. want to extend the life of the processor as much as possible. If I ditch the sabertooth however, will the ASUS P8Z77-V LK be a good choice for SLI with the dual 680s?