Woods what kind of system do you want? water volume? DI only or RO? heated or cold? etc etc
In a perfect world all the working parts, pumps, DI vessels etc would be positioned and protected within an insulated closed cabinet door to protect from damage, freezing temps etc.
Mine has this, baffled tank 650 LT all working parts enclosed within a thermal insulated cabinet door, "apart from the 9KW heater add on PF" the system is original, anchorage system could be improved, but apart from that all the WFP suppliers could learn a lot from the simple design of this baffled tank with insulated cabinet.
When temps drop below freezing, hose reels and poles go inside the garage, nothing within my van mount system has ever froze since 2006. And looks so tidy, black tank with all working parts within the cabinet. Flow controllers on the side of the tank and nothing to get knocked or damaged.