Maybe you saw this on Kickstarter in 2012 (check that link on the Kickstarter site for a sweet video with this uke). The Plastic Ukulele! Here's the scoop according the developer, Scott Seelye...
"The Plastic Ukulele will be 6 parts injection molded from polycarbonate,
often referred to as bullet proof plastic and not affected by humidity
or temperature changes. These parts are then assembled to create a very
strong hollow structure with the internal volume and tone of a much
larger instrument"