I live in Idaho, and have seen quite a few modifications done to ATV's, UTV's etc, but never anything to lift concrete blocks. However there is a lift system for ATV's to lift game onto the racks of an ATV, so it might work on a UTV with some modifications.
Here's a link to a site that sells them. It shows it lifting hay bales so I'm sure it would be quite capable of lifting some concrete blocks.
ATV Loader and ATV Game Hauler by Hook-A-RackŪ
Hope this helps. Seems like a pretty good system, and in the photo gallery it shows it being operated on the rear of a UTV, so I'm sure it would work on a rhino too.