Bit odd that folks are putting bags of groceries out back in the bed.
I've got plenty of room in the back seat of my SuperCab, and those of you with crew cabs have even more inside room.
But if you take five people on your grocery buying excursions, then I see the problem.

My Lariat's bed does have four vertical "ribs" molded into the sidewalls about a foot in from the tailgate.
I suspect that a properly cut 2x8 would fit into either one of the three "grooves" nicely, giving you an adjustable storage space back there.
You'd want to cut that 2x8 for a snug cross-bed fit so it won't pop out going over bumps...

 

drop-in bedliner + 2x4

 

Boom. Done.

 

I had the drop-in bedliner on my old Ranger and did similar with a 2x6.
But I did a Line-X spray-in on my new truck, so it's good that those ribs are stamped into the aluminum bed walls...

 

I just realized that bed divider attaches where the cleats are? I've been thinking of building something that would hang on the cleats but haven't gotten around to it. $200 seems a little pricey but it does look good.

Edit: Found a couple of different threads here:
https://www.f150forum.com/f118/so-wh...-there-300403/
https://www.f150forum.com/f118/bed-divider-313427/

Also it looks like these "E track" cleats work with the box link stuff?

 

Hi Ktunis,
Great to hear you are enjoying your system! Please let us know if you have any feedback.
Cheers!