Cooking with Tofurky for the Holidays offers various recipes for tofurky, including a Glazed Tofurky. Martha Stewart Living (November 2006) has four holiday dishes for vegetarians, including a Quinoa Pie with Butternut Squash that sounds excellent, but I cannot seem to locate the recipe online. Very few other magazines offered much in the way of vegetarian dishes.
If you want to make your own tofu turkey, All Recipes has a Tofu Turkey I that sounds pretty good (it calls for mushrooms, dried sage, tamari, and miso paste, among other ingredients). Over at the Washington Post, a discussion of vegetarian Thanksgiving options, including suggestions for winter squash lasagna and mushroom risotto as vegetarian main courses.
And for those hosting Thanksgiving, a gentle reminder: something cooked with chicken stock is usually not okay for vegetarians. Just because there are no chunks of meat present doesn't mean it's "vegetarian." It's nice to offer a dish or two that are completely free of animal products, especially if you know you'll have vegetarians or vegans in attendance. [Thanks Rebecca!]