i see no market for coloured e-ink
I reckon that the "e-books in colour" fans will use tablets - android, apple, MS windows 8... - as part of a general shift to multimedia "books" with embedded audio, video....
latest tablets offer "retina display" quality as the expense of some eye strain & shorter battery life, & publishers can package the book with the movie of the book, or the book of the movie; and can offer the graphic comic for the literary challenged, the audio book for the visually challenged...
there is just so much more scope to sell stuff to a tablet owner, compared with a hypothetical colour e-book owner. The commercial failure of 10 inch e-readers like K2 also suggest a shift to tablets/netbooks.. for business users
single-purpose dedicated e-book readers will continue in B&W , expect the laggards to add back light to their range to compete with paperwhite & nook glow, or to quit the marketplace ( Sony don't seem to know what to do! )