well my point was that the dpi on text won't really matter going from 150->300, regardless..
http://www.mirasoldisplays.com/mobil...mod-technology
they have a demo but it's not a real video so there is no way to know like you said
don't know if they even have a working prototype yet, but once it's out there we will probably start seeing it it netbooks/phones/readers
Refresh rate looks low (5-15) which is still pretty decent for an e-reader.
I'm no engineer, but the way they describe the technology in the video, it looks like the attraction of the plates requires constant current to retain pixel state, similar to how LCD works. The only advantage is that you won't have a backlight sucking up energy so you will still get relatively long life. I could be completely wrong however. As far as # of colors, doubt that a single pixel can be regulated that much with that small space, so I'm guessing 32-128, but again random guess on my part =X.