There’s no word yet on when the new screen might hit the market, but I do know that it can display 4 thousand colors (4,096 to be exact) with a resolution of 75ppi. While that might seem awfully low, there’s a reason for it. Plastic Logic added color to their existing screen in much the same way that E-ink did.
The color is provided by a filter lying on top of the grayscale screen. The screen underneath the filter has a resolution of 150 ppi, and that gets cut in half because you need 3 pixels to do red, green, and blue. There’s also a 4th pixel which is left alone (it shows the white/black of the underlying screen. The RGBW are arranged in a 2 by 2 grid in the layer on top of the Plastic Logic screen.