Oops.. Pics continued!
Hope these give you some help with ideas.
Paratroopers Stay Up Longer!
KRay, they do make boxes that will work with the sub yes. I like the double option (box/rack).
If someone needs a spot to sleep, the box can be removed, but your other stuff can stay in the rack. I know a guy with that rack, he actually sleeps in his jeep (4dr) and that rack is used as a dog bed.
Paratroopers Stay Up Longer!