I was in Taitung on business and found a Loving Hut, a nice vegan chain. I frequent Loving Hut in Taipei. The menu had some hot pot and a couple fusion dishes with mock meats. I can't complain; I was just happy to find vegan food in Taitung! The staff was friendly and one man behind the counter even spoke a little English. Menu in Chinese/English.
Cons: Not too much variety on menu