Bed crossbars?

[ablock]

Just bought a Limited with RamBox. Our car has roof crossbars which are handy because you can install lots of different carriage accessories, like bike and kayak racks. I'd like to reuse the racks we already have, which I could do if there is a way to get a pair of simple crossbars that drop in to the bed slots. Alternatively I could use bars that mount in the tie-down extrusions, but I would prefer the bars to be closer to the bed floor.

Does anyone make such a thing?

Thanks!

 

[ablock]

I guess there's these utility bars but as I said something that sits in the base of the bed would be better.