there are people that will build anything you want in terms of custom coils. i have a rep i use in pa but i'm sure there are some near you. look into guys that make replacement coils they can usually help you.
ThermaStor's 119 gallon tank will handle up to 25 tons on R22 and are often paralleled together for higher loads. If your water heating load is more less than what the available superheat will give you they can be installed with a discharge gas bypass regulator, ie you could have two tanks good for 50 tons and a differential pressure regulator like an A4AD will bypass the balance of the flow based on pressure drop across the heat exchangers.