Sharp recently sampled a few of their 32" 4K monitors to Microsoft's Extreme Windows. The blog, known for editorializing what enthusiasts can do with Microsoft products, combined three 3840 x 2160 monitors into a 3×1 Eyefinity configuration at 60 Hz; the screen, itself, measures about 7 feet diagonally. This configuration, unlike the already-supported three-display 30 Hz and single-display 60Hz 4K modes, required AMD to develop a customized driver before Sharp's repo-team reclaimed their $15,000 worth of monitors.
They had a day until their door was to be knocked.
The system, three Radeon HD 7970s in Crossfire, successfully drove… they were playing Dirt 3, by the way… the three monitors at 60 Hz with between 62 and 70, of software recorded, FPS. 11,520 x 2160, at 60 Hz, requires 1.5 billion colors to be calculated within a second of animation; that is 1.5 gigapixels. Ignore, for a moment, stutter caused by including Crossfire with an Eyefinity setup. Every calculation, whether properly drawn to the monitor or not is, and must be, performed; 1.5 gigapixels is impressive and an accomplishment for Radeon hardware.
Lastly, I need to call out drama as I see it: power supplies. It is not hard to find a PSU which can support a three-GPU system and no reason for it to be hanging outside the case. It might give off the bleeding-edge appearance, but this is not arc welding. If they really were concerned, they could have picked up a higher capacity device from the shelf of a local component reseller.