A $50 smartphone with e-ink and 7 day batteries might take emerging markets by storm.
It didn't had much success in Perú. (although I'm an avid fan an ex-user of it)
Why do you think it hasn't cautious on in Peru. What would catch on there?
The phone had 3 mayor design issues. At least from my POV. First, I couldn't write . in in text messages. I had , @ even £ but alas, no .! Then there was the issue that all sound went increscendo, thing is the message notification was to short for the sound to reach an audible level. And last, as the e-ink only consumes power to paint the screen if you manage to run out of battery You wouldn't realize immediately as the screen was still showing what it showed before running out of power.
I think what would catch is something cheap that seems pretty/expensive.
Something with just a little more capability than a "dumb" phone or feature-phone but with a more comfortable interface and 7 days battery life would be able to capture the market. Let's say, one builds "visual voicemail" and add some sort of more user-friendly banking front end which still uses the current SMS channels. Combine that with light web browsing and something like Wikipedia and Twitter/Facebook, and you'd have it.