I've gone "meatless" before and I go real heavy on the cruciferous vegetables and beans. However, I tend to alternate between that and a regular diet. Especially, because Baseball season is coming up and a bag of peanuts just doesn't cut it. Turner Field does offer a "Veggie" dog but it's nothing like an actual hot dog.
It's difficult to find a good tasting meat substitute when you want something familiar. I love Boca burgers (their classic American burger is delicious!). On the hot dog front, I've yet to find a good alternative.