I don't have a Dodge but here is the one I have. It slides into the driver's side frame rail. It can hold 10 or so suitcase weights. I need to come up with a better way to secure them though. The tabs on the side and a ratchet strap is a bit tacky.
The tubing is 3" sq. w/ 1/4" wall and the plate is 1/2". It probably weights about 40lbs give or take a little
I actually bought this from someone who used it. I have yet to use it though. If/when I build my one of my own, it WILL be different than this.