Eventually I'll get around to updating the OP, but right now the rumors of the new 980 Ti have begun showing up. It's supposedly going to be a bit faster than the Titan X, be priced about $300 cheaper, but have only 6GB of VRAM. I'm sure that'll be a nice GPU to grab three of in order to start up my 4K multiboxing again.

http://wccftech.com/nvidia-geforce-g...coming-summer/
http://www.sweclockers.com/nyhet/202...efter-sommaren

In other news, nVidia is planning to allow 8-way SLI with their next generation of GPUs (Pascal). I might have to get some crowdsource funding going on so that we can get some benchmarks with that... for multiboxing science!