We will be visiting Austin (slightly N. in Cedar Park) for the holidays and have a couple of vegans among us. We don't want them to starve, even though the rest of us are ravenous pork-loving carnivors. We would like to go out at least a couple of times. Any thoughts?
You have lots of options, and many of them not necessarily designated "vegan" restaurants. Are you looking for true vegan dining options, or just places where your vegan friends can eat? And what cuisine are you all hoping to eat when you're here? Ruby's bbq has some great vegan options on the menu and some really solid bbq, while Mr. Natural is a vegan/veggie mexican place with vegan desserts and pastry. Austin is a pretty veggie friendly town, so a lot of it depends on what you're looking for.
Off the top of my head, I can think of Casa de Luz (http://www.casadeluz.org/) and DaVine Foods (http://www.davinefoods.com/). I haven't tried either of them, but they have devoted fanbases (well, Casa de Luz does; DaVine is fairly new). Mother's is awesome, IMHO, and they offer vegan versions of their menu items (the whole menu is vegetarian).
Good luck and enjoy.
Also, Kirbey Lane Cafe has a great menu with options for everyone....and there are tons of Indian places north (Madras Pavillion, Swad, Curry in Hurry) that are delicious and have plenty of vegan options.
Oh, and I have been, but the place next to Toy Joy on Guadulupe...Dhaba Joy is all vegan and features sandwiches, ice cream...desserts. I have had some of their sweets which were great, but not lunch. http://www.dhabajoy.com/
That reminds me...
Virtually across the street from Toy Joy and Dhaba Joy is Ruby's BBQ (30th and Guadalupe). They have a few vegetarian options (vegan if you omit the cheese). I'm a vegetarian (not vegan), and I think their black bean and cilantro tacos are amongst the best in Austin (especially with the pico de gaillo AND the BBQ sauce). The carnivores/omnivores can enjoy Ruby's organic beef, Elgin sausage, or other barbequed delicacies and yummy sides.