Although Taco Bell could seem safe since many of its products are corn-based, it is not safe for people who are especially sensitive to gluten. Its own website says that all of the products may contain gluten, even though some specifically don't contain wheat. I know some gluten-free people who can eat at Taco Bell without a problem, and some who can't.
I don't risk it because the after-effects are not worth a few TB tacos for me. It's too bad though because TB could have been one of the few "safe" fast food restaurants for us gluten-free folk.