Ladder or lumber rack for Tahoe?

[PatDTN]

I work as a handyman and sometimes need to be able to carry a 24 foot ladder or a sheet or two of plywood and maybe some other lumber.

I'd like a rack that would let me toss that kind of stuff up there and tie it down. I learned I also need just a bit more height than stock to let things clear my tailgate diffuser at the top so I can raise the tailgate with things on the rack. Weight carrying of course makes a difference. Also since the wind will get under a sheet of plywood it needs to withstand lifting.

The standard roof racks don't look like they're very sturdily mounted. Is there enough structure in the roof to do something like this? Does someone make and sell these?

Thanks.