Lenovo Twist.. Instead of 2 separate screens, Y not place a transparent OLED in front of the e-ink display? The OLED can be used as an actual screen or used as a light panel for the ink screen behind it. The ink display can be used as an ink display is normally used or it can be used as a static BG for the OLED in front of it. You could do something crazy like make the OLED screen display the same image as the ink screen but at mid-opacity or even make the ink screen display only blacks/grayscale while the OLED only displays color.