Yeah, my pop's truck has one of the older ones that take up a lot of room.
There's some newer ones that are nicer that do support some weight (a few hundred pounds). Their mechanism/storage is also a lot smaller (about 8" x 8") so you're not giving up much space.
I plan on having a rack on it so I'm not looking for the lid to support much weight, just to keep things relatively dust, water and sticky finger free.