About ten years ago I bought a carry on from High Sierra named Endeavors™ Executive 22" Expandable Wheeled S.U.T. North-South.
It had one full-length bottom compartment, plus two smaller compartments (one larger and one smaller) hinged at the long ends of the bottom compartment and folded on top, to complete the shape of a regular carry on when closed.
Here is a old image I found, although it is small and it's hard to see how the piece works:
It was incredibly practical (because of the three separate compartments and ease of access) and ultimately, my favorite configuration for luggage, ever.
I have been looking for something like this for a while now and have not found it on any of the usual luggage retailer sites.
Does anyone know if someone makes/sells something like this?