Why would you want a cell phone with e-ink? It wouldn't improve the standby time at all since that's determined by the radio, not the screen. Sunlight readability would be nice but there are LCDs that are pretty good and anything interactive would be painful on a slow e-ink display.

    It wouldn't improve the standby time at all since 
    that's determined by the radio, not the screen.

In smartphones the display is the biggest consumer of battery.

For instance, I rarely use my Android smartphone, other than for making calls / reading emails (and I really don't do that frequently), and the display is usually eating up ~ 30% of my battery, even though I always keep my data connection + sync ON. And there's nothing that drains my battery faster than doing Internet browsing, with the stats on my Android showing the display taking more than 50% of battery life. And if I'm outside, in the sun, browsing the web ; to make the screen readable I have to increase luminosity, and so my phone drops dead in 2-3 hours.

Another example - I also have an old Nokia 1100 - it's absolutely insane how the battery lasts for a whole week. If you can make your smartphone last for 6-7 days with whatever you want turned off, let me know ;)

I would also like an e-Ink smartphone, since it would be perfect for reading emails, in direct sunlight and also increase the battery life to more than 1 day - yeah, that would be awesome.

If the screen uses 30% of your battery then switching to e-ink would be a 30% improvement at best. Hardly Nokia 1100 territory. Though it would be so slow and annoying to use that you wouldn't use it as much, so that would "help" too. Also, need I remind you that your Nokia 1100 has an LCD screen?

The Nokia 1100 has an LCD screen indeed, but it is black and white, without much luminosity.

Right; the only resl advantage e-ink has over this type of low-power LCD is brightness, and it comes at the cost of 1+ second response time with flickering. A terrible trade off for an interactive phone.

Looking at battery use statistics in my phone:

Voice calls - 33% Android System - 13% Maps - 12% Display - 11% Dialer - 11% Youtube - 10% Cell standby - 7% Phone idle - 4% Camera - 3%

The display does not seem to be particularly bad.

I saw a grey-scale style calendar (branded with a pharmaceutical brand) in a pharmacy the other day. I asked if it was an e-ink display and they said yes. Then they realised it was just an old-style flip-page calendar which LOOKED like e-ink.

Amazon should do a tablet with a LCD screen on one side and eInk on the other. They can share a lot of components (battery, CPU, radios), so it may not be as bulky as one might think. And then you could read a book inside on LCD, step outside, flip the device over and you're reading the same page in eInk. Likewise for webpages.

There is, or at least was, actually at least one dual LCD/eInk display. It is called the Pixel Qi.

Yeah the Pixel Qi and Mirasol displays just never looked very good IMO. I saw the Notion Ink Adam videos in sunlight and it didn't look very good. Nothing like the Kindle. I think the technology to do both in a single display is just not there. Otherwise I think Amazon would have used it.

I saw a Mirasol device (demo model) and it was lovely, both in sunlight and indoors.

You can - or could - get cell phones with E-ink displays. Like the Motorola Fone:

http://en.wikipedia.org/wiki/Motorola_FONE

...it just happened to be rather basic. Perhaps that was the point.

I am aware of that phone, but I was never able to find them for sale at anything close to a reasonable price.

I imported one for $50 and have had it for 4 years. It's only passable as a phone to be honest as the old eink display used could only show a few types of characters (no uppercase letters!). I'd be very interested in a new eink display phone but my standards for acceptable UI has been raised by modern smartphones.