Aluminum test mules in service since 2011?
 

Owners Didn't Know They Were Driving 2015 Ford F-150 Prototypes [Update]

Interesting...

I spent a day with Ford engineers at the Barrick Gold Cortez mine in Nevada where two of the X1 prototypes are being tested. Story is here: 2015 F-150: The Story Behind The Bed | Medium Duty Work Truck Info

That's a neat story, and it's must easier for the buying public to relate to than some lab test.