Are you lifting suitcase or wheel weights? There was a picture of a puller that had a winch on the center of his tractor. He would drive over the weight box and the winch would lift it up to the belly of the tracror. Easy way to gain a 1000 lbs.
You could mount a simple crane like this and change out the manual winch for a cheap 12v.http://www.princessauto.com/pal/en/Truck-Cranes/Pickup-Truck-Mount-Crane/8169419.p