Funny thing happened. I dug around my parents' basement and found my old AirWaterIce RO/DI system. It was a 5 stage, 75 gpd one. Still in perfect condition. I just ordered a new membrane, and filters (with one upgraded to the filter for chloramines).
Another crazy thing I found was my pretty new chiller sitting under a pile of my dad's shoe boxes, and all my RO/DI, topoff, and auto water changing system lines still piped throughout the basement and into the living room of their house. I even found some lifereef dosing pumps. Amazing. So I'm pulling all those lines out and bringing them back to my place. There's even a huge brute tub with a float valve that, interestingly, still is full of water.
Pretty sure the last time I had a tank was in 2008 or 2009? Crazy that there's still water in that tub...