First aid - looking for the perfect case

Hi everyone, new owner of a black 2014 Prius here!

I want to have a complete emergency case in my car, and I'd really like for it to be in the space underneath the cargo, but I'm having trouble finding the "perfect case".

For now I found the Nanuk 923 that meets the height constraint, but it's a bit small, and expensive because of the locks on it (which I definitely don't need).

I measured 6 1/4" of height clearance space in this compartment, but all of the nice rugged case and something like 7" in height.
My ideal dimensions would be something like 22 x 14 x 6 ", but I don't seem to find something nice at the size.

Has any had any luck with something similar?