Of course, this is just my opinion, and a ton of older vehicles that are considered cars would fall into this category. Heck, a standard Jeep Wrangler would fall into this category.
Furthermore, there isn't any reason you couldn't make a truck (that is, a pickup) using a unibody approach, but I don't know of any examples (which just may be my ignorance).
Regardless - I always consider anything modern with a ladder frame to be a "truck". It may not be a pickup, but to me it's still a truck.
Remove the backseat and top - ultra-shortbed pickup!
Also this:
https://en.wikipedia.org/wiki/Jeep_Comanche
Then there's this:
https://gr8tops.com/shop/jeepmodels/jk-wrangler/jeep-wrangle...
And finally:
http://www.roadandtrack.com/new-cars/future-cars/news/a29009...
For me, having a permanent bed cover means it's not useful as a truck.
It also has a recommended cargo weight of 6,000 pounds, so it can haul a ton (literally! and two more!) of shit.
This is really no less of a truck than a Ford Bronco or Dodge Ramcharger.
Even so, though - there are plenty of consumer pickup models which are used commercially, and more than a few can handle some pretty big loads (especially towing)...