Grindmaster
Grindmaster doesn't carry as many models as Bunn, but they are another choice for a volume tea brewer. They work in the same way as the Bunn brewers, making several gallons of tea at a time into a large dispensing pot or carafe.
Neither machine is cheap, and with price tags of several hundreds of dollars they aren't really intended for residential or occasional use. But if you need to serve hot or iced tea to a large number of people regularly, one of these tea brewers can save you a lot of time.