Bunn Bunn iced tea machines are a bit different, as they are commercial-grade brewers that you can use to brew gallons of iced tea for any kind of gathering. There are several models available, usually capable of making between 3 and 5 gallons of tea at a time. There is even one that holds sugar or sweetener, and can sweeten up the tea right as it brews.
These machines don't hold ice, so you would have to have ice cubes available for the tea once it's dispensed into glasses or pitchers. And the machines themselves are made to hold large airpots, which are thermal canisters that you can use to carry your fresh tea if you are bringing it someplace before serving it. The airport has a spigot, so you can just set it out on a table, and people can pour their own glasses of tea over ice.