Ya I was thinking of designing an underfloor space to fit say 20 robust 5-gal squarish / stackable tanks.
Rather than having to pump out to lighten up (requires another big tank),
be able to just "unpack" some or all the water-cubes to the site, then
travel from there with a much lighter load.
Same with propane, I got a 4' x 20" 80-gal ACME tank real cheap, I could use, but
now thinking a bunch of 20# BBQs in a similar setup would give a lot more flexibility, probably get a decent price back for the big tank if I was patient.