There is a mod for a dry van trailer with a car lift on the side. It’s on the repo, I couldn’t find it in my brief search but it’s out there.
Also AR162b's semi addon pack has car lift, but I think it did not work 100%, there was problem with rear door not lowering down to ground, only half way. Then there is even one more, not sure which semi addon pack it was, but it did add car lift rear door to cargo box. However I'm not sure if even all those are quite what OP was after.
Easy way to make such would be this, but just not quite so accurate, making it wider would be lot more work: Another mock up, just very crude mesh, no jbeam and low resolution texture from textures.com, just few minutes of work, might not be what OP wanted though, but idea how such easy to make mod could look:
Yeah looking back it made no sense for me to say that, but it was also over a year ago, so you just did the same thing lol