Coldfront, they make those cherry picker loaders that can bolt to your truck. We've had some threads on them before. I don't think for a "forever" purchase that they are that expensive, and can be moved to a new truck or trailer, etc.
But you want it on your trailer, so you can move more wood at once, and split it at home, correct? Leave splitter at home? Small branches and saws and gear in the truck, larger rounds use the crane into the trailer.
I just looked, both harbor freight and northern tool have them, pickup truck cranes. Supposedly, just make the mounting deal a little more robust and use beefy bolts. You should be able to use some log tongs to load your big rounds.