Here's some ideas. I'd love a jerry can rack on the back of my TJ. I have seen a TJ getting around up north QLD with a roof rack loaded with about 6 of those little 5 litre black plastic jerry cans spread out to even the weight.
Check this out: Off-Road Receiver Rack
Frame made of heavy duty tubular steel with reinforced steel flooring
Mounts into any 2" receiver hitch
Black powder coated steel construction
Convenient storage system for excess luggage, cooler, camping gear, etc.
Deep storage bin to secure cargo
Hauls up to 500 lbs.
This is all Steel Horse stuff.