My Brother has one. A Mitsubishi brand, 4x4, with a dump bed that's rated for about 700 pounds. (Of course it can hold more, and has, but that's not what the factory recommends. The rating given to that vehicle's cargo capacity in the bed is on the low side.)
10 years ago when he got it, these were not legal for street use so it had to be trailered to the property and left there like an ATV or a Gator. I heard that now the industry has lobbied the government to amend the law so that you can actually get a license plate on these and drive them on the streets, but I haven't confirmed that.
As for parts, they are hard to find and expensive. Some parts can be found here in the US as used parts cannibalized from other of these type of vehicles. If you need to get a new part from Japan, there are some companies that specialize in import of auto parts from Japan for non-standard vehicles like this. But you'll pay a good penny and you'll have to wait a while for it to arrive.