I think a 2 page device could be cool...
Primary e-ink display with super battery life, super high quality text...
Secondary display (which could be disabled when not necessary) across the page, maybe oled so still decent battery life but brilliant colours etc).
I think ideally, if you could get the eink screen with haptic feedback and touch capability, there's no reason you couldn't power up the device to use in a laptop style format rather than a book one when the mood suited you (of course you'd need a clever hinge to tuck away the shiny colour screen). Because a keyboard doesn't really change layout, the eink screen would work fine for it in my opinion, as well as offering an interesinting alternative to a trackpad or similar, by way of a whole screen
I'd love to see a company (one who's given it more thought than me hopefully
) make something like this