I don't see any limits in the areas you suggest. It's true that the eye's ability to perceive detail is limited, if we want to take in the entire screen at once. But we can always look at just a portion of the screen at a time, as we do with murals, large paintings, the entire scenery around us :-). As for limits to manufacturing the screen, that's limited by power consumption (but reflective pixels can be very low power), CPU/GPU speed for calculating changing scenes, and the wiring or other schemes for communicating with the pixels. But none of those seem outright show stoppers (so to speak), just costs, which seem on a downward trajectory. Some people expect us to have vast walls of video wallpaper... and one doesn't heat categorical problems with that.