I have an old Kawasaki Mule with the variable belt drive and had no problems with it. I routinely pull my 4x8' utility trailer loaded to the top of the sides(HomeDepot SnowBear Utility)with oak and maple logs, 6 to 8 inch in diameter, on the flat with no problem. If I have a problem, it's traction, as it's a 2wd unit. I wouldn't worry about the clutch/belt system, so long as they're using a good one
My son-in-law was at the Moncton RV show over the weekend and said that Kioti had one of their UTV's there. He said his brother took some pictures, I'm trying my best to get a hold of them.
Steve