I tried a couple of "local is lekker" versions based on golf carts and own designs, but the problem was with getting appropriate tyres for the sand. Tried a variety that I could get hold of, but they either did not work lekker in loose sand, and those that did (pneumatic go-cart weels) were too expensive, and too heavy if you get to a spot where you need to pick it up onto the rocks or onto the back of the bakkie.
I bet you you cannot solve this problem
I can get Go kart tyres by the thousand. I just don't think the guys would spend more than a grand on a cart of any description. I think the carts are only too heavy because of what it's been loaded with.