I’m not sure you’ll find any ideas here you actually will want to use, but these are sure creative!
From the movie Beasts of the Southern Wild, there is this pickup truck bed with barrels.
Cubans inspired by desperation and the materials they had at hand. One of these was for sale on Ebay at one time.
Then there is this from YOUTUBE: This video was filmed in 1990, at Paradise Point Marina, in Stockton, CA. For years I thought it had been taped over until I found it recently. The shop I worked for helped with some hardware for this creation. The owner had plans to develop this into something for all vehicles, from compacts to RVs. You know you didn’t have to tow your boat when you could just drive you car into the lake and ski behind it. I don’t know that it ever went any further than this though.
One more for good measure, though I have no info on it