Member III
Water: Consider a dromedary bag? They're less wieldy, but you could get several 10Liter bags and slip them into places a 7-gallon cube can't fit. This also puts your water in several separate containers, which means you're less likely to lose it all if it leaks.
Second on that one.. the other benefit is that you don't have the gurgle of a partially empty (half full, optimist) water tank in the back of the vehicle. I hate that racket.