I got it from Home Depot for cheap. They don't list it in stock now: Rubbermaid Victory 2 Gal. Red Cooler FG153004MODRD - The Home DepotVideo was really informative. I especially like the smaller igloo cooler you were able to find. Had to do a quick search and nothing yet, but I am going to keep my eye out. I do like that with the smaller batches you were able to brew two days in a row without much added effort.
There might be a good way to just insulate your kettle. Maybe with some layers of Reflectix or other insulation?