Yup, the memory LCDs seem to have all the advantages of e-ink with none of the disadvantages. Better refresh rate, and only needs powering at all when you're updating the display. 

Also I dunno that E-ink touchscreens are possible, the one on my ebook uses a grid of LEDs / photosensors to detect touch. The Sharp LCD is mostly ordinary LCD, I'd guess that you can get them with resistive touchscreens already fitted.

This is an awesome idea, and I think it is the future of devices. Once Moore's law tops out, people are going to look at other ways to improve the experience, and baterry life is a high priority. I would love to have a smartphone that would last for days on a single charge, and I'm also in love with e-ink displays!

I really like e-ink screens and would opt for something similar. Good idea

Nice idea, though i would suggest also looking at other types of screens, e-ink are pretty rad, but they all have pretty medicore refresh rates, and if you play your cards right you can still save alot of energy on the screen even if its not a e-ink screen.

For example, OLED screens take less power then your average LCD, and if you start avoiding overuse of the 'color' white you can save quite alot of power.

All of the above assumes that you will want to show some animations or maybe even watch a video, if you dont, then e-ink will actually be your best bet.

Keep us posted, interesting stuff!

Sharp Memory LCD would be another option.