I don't think the issue is gearing or power. The issue is wheel base. Because the jeep is short it's not stable pulling weight and could jackknife when trying to stop.
I've also read that cooling can be an issue when towing a lot of weight and not great for your tranny. I reckon you'd be fine over short distances if you take it easy, but I sure wouldn't want to drive any great distances pulling weight that isn't recommended. Jeep don't recommend such pathetically low tow ratings for fun, but for safety.