I know a lot about them. That is a Ural Cargo Box, and I have one. They are not made anymore, and are very hard to find. If I didn't have one already, I'd be all over that.
They have a top hinged gate in front, and actually have a dump mechanism. You fill it full of dirt, pull up to the hole in the ground, and dump the load into the hole, then back away. That was the premise. Most people never used the dump mechanism, and just welded the hinge down to the subframe. Mine is like that. Rhino line the inside, and you've got the perfect small pickup truck in sidecar form.
Cleaned up, it can look a little something like this.