The Gladiator has a decent enough payload capacity of up to 1600lbs but keep in mind thats a stripped down base model gas motor. Find the one you like and look for the yellow decal drivers side door jam as mentioned before. That will give you the payload for that specific unit. A loaded trailer with a GVWR of 5000lbs can put as much as 1200lbs on the hitch. a loaded/ fully optioned Gladiator would probably have a payload cap of 1300lbs leaving you with only 300lbs for passengers gear etc, which would make for an unpleasant experience.
Remember the published numbers you see are always the VERY BEST SCENARIO and dealers never bring in base base models because there is no money in them, so they bring in the high dollar, lots of options models so they can make margin. The chances of you finding a Gladiator with a 1600lbs payload are really really slim. A half ton isnt much better