Yeah I'm getting the same conclusion as I look at what's available. Now thinking of rolling my own using tailer deck technology. An angle steel welded frame with 2"×X wood slats. You would need a torch to get through it, and I could transport pallets of bricks on top it*. Of course it would be heavy as hell and would require a lift assist, maybe an electric actuator.
*Not sure how the bed would feel about all that weight resting on its rails, maybe pallets of bricks aren't in cards, but certainly "stuff" could ride on the bed cover.
The "trailer deck" bed cover would take me back to the situation with the awkward giant lid that precludes getting up in the bed to root around for stuff without hitting one's head. Other idea is several sections of reinforced interlocking aluminum plate. Similar to the 3- or 4-piece folding or accordion hard toneau, but the sections aren't connected. They can be removed one at a time and they each lock down to the bed rail.