I know that the DES displays go up to 10.1", but I haven't seen displays beyond that size (though I'm unsure if they intend to make larger displays in the future). For the Sharp Memory Displays, I think I may have spoken too soon - looks like they top out at 4.4" currently, which of course wouldn't work for your application.
RLCD is an interesting option, I guess the sacrifice there is readability angles and paper-like-ness?
Ones with good viewing angles exist, but for sure there isn't paper-like-ness and you loose the no zero-power persistence of e-ink. But you get fast, artifact-free refreshes, perfect sunlight readability, at very low power consumption. (No backlight which can be a pro and a con...if only a more modern Pixel Qi type panel existed.)
RLCD is an interesting option, I guess the sacrifice there is readability angles and paper-like-ness?