I kept thinking about this. Then I did some searches. The only examples with photos that I could find were scale model toys. This was the best. It actually gave John Deere model numbers.
model 963 running gear + model 150 hoist = a cheaper dump trailer
While it is a photo of a scale model toy, it does illustrate the idea. I'm sure other manufacturers offered the same type set-up. While doing the searches under "barge wagon" a number of hits came back for auctions.
This gets me thinking. A trailer like this would be ideal for hauling firewood, compost, leaves, kids - whatever. Might have to start looking around...maybe find one. Even build one. Local farm trader newsletter has NEW 5 ton running gear with rims, no tires for $459. Used hay wagon trailer in same publication for $150. Trip to the scrap yard might be in order.