Hi there,
This may be easier for you: Farm Fresh. They have a huge natural foods section that has frozen pizzas that are dairy free in them. I've had to, one by one, take my kids off all dairy for several weeks at a time to rule out a dairy allergy, so it was important that there be absolutely no diary or dairy proteins in it. I can't remember the brand, but just read the back and you can see what's dairy free.
Their actual dairy section at Farm Fresh actually does contain dairy free cheese, mentioned earlier, the Tofutti slices. Tofutti is my favorite brand of dairy free cheese, it tastes better than your average soy cheese.
Good luck!