I have Diamondback HD cover thats only one year old. Its meant for hauling ATVs on top of your pickup bed and you can still store items below and lock them. Has a max weight of 1600 pounds. I never used it to haul an ATV since my four wheeler broke shortly after I purchased this. I have all the ramps and Accessories. Would be willing to trade for shotguns, rifles, or handguns. 
Mine came off a 2019 Ford Ranger with a 5ft bed, so it will only fit shortbed pickups. I have 9.5ft folding ramps so they still fit under the cover.