I have a ladder rack like this.
650 LB 2-BAR ADJUSTABLE TRUCK LADDER RACK PICK UP UNIVERSAL LUMBER KAYAK UTILITY | eBay

It's light weight metal, I transport 2 kayaks on top. I want to add another rack to transport another 2 kayaks. Mine cost less than $70. You know anyone in the Memphis midsouth area that would add on to this for about half that price?