The first thing that came to mind was the Nokia Gem concept from around 2011:

http://conversations.nokia.com/2011/11/10/nokia-gem-what-sor...

The whole thing was a touch screen.

Here's an Engadget article on the Nokia concept with a fair amount of comments:

http://www.engadget.com/2011/11/11/nokia-gem-concept-dazzles...