Hi,
I would like Ben to build a Raspberry pi zero smartphone, it would be cool to use this small new pi zero with a touch screen, a cellular module (i.e. adafruit FONA 3g cellular + gps), battery and create a simple graphic interface for making phone calls, sms, web browsing, and other cool stuff today's smartphones do.
The submit show idea it's very cool!! 
Hoping that you'll like my idea and give it a try!!
Best regards, Alex.