[fjtorres]

The problem with big screens--eink or lcd--is that they are currently built on glass substrates and that makes them fragile. The bigger the screen, the more susceptible to bending damage and the more reinforcement they need, which means extra weight.
Display makers have been working on metal foil and (better) plastic substrates for displays and we're just starting to see the first low volume production runs for B&W eink on plastic.
If they can get the process running at high enough yields, we might see it applied to large format B&W some time *next* year. Color is further away. High volume (low cost) is even further out.
The key problem for large format *color* is that LCD and battery tech is already close to offering adequate battery life so it won't take much incremental improvement to get a dedicated color reader with "all-day" battery life. But the price and weight would be too close to that tablet space and most consumers would more likely opt for a slightly higher price and full tablet features.

Realistically; good color eink is years away and when it arrives it may find the way blocked by LCD at the high end so its future will remain tied to the low end. Which means that the future of dedicated readers will be small and cheap for the forseeable future. (3-5 years)