Class A's with big fresh water capacity

I'd figure out what manufacturers have a unit that you might be interested in and send them all an email asking your question.
bumpy

That length is more likely to have no more than a 50-60 gallon capacity. It's easy enough to carry extra 5-7 gallon jugs of water in a storage bin though. The on board pump can be set up to draw it out the jugs to replenish the main tank, if the RV isn't already equipped that way.