Originally Posted by nakman
My other thought is just scrap that idea, and instead do an internal support cage of some type-so you've got a couple bars below the rack rails, and some legs that run down to the wheel wells/truck bed? In that situation your topper isn't really doing anything other than acting like a fiberglass washer for your RTT support system, and keeping the load from swaying side to side.... but all the load is transferred down to the truck bed. I kind of like this idea better.
I swear an internal support system was available from some manufacturer. I thought it was Rhino-Rack but can't find it in their on-line catalog. I have a hard copy catalog at home and will check it tonight.