Yes, they do exist. Kudos to ABC Bakers for making a few of their cookies vegan. From their FAQ:
Yes, ABC has 4 vegan cookies in our product line – our Lemonades, Thanks-A-Lot, Thin Mints and Peanut Butter Patties are all vegan.
Unfortunately, the other supplier for the Girl Scouts, Little Brownie Bakers doesn't have any vegan options.
Chicagoland's Girl Scout cookies are made by Little Brownie Bakers, so there aren't any vegan options for us. Still, it's good to see that delicious treats like the peanut butter patties can be made without any eggs or dairy.
If you're curious to see who makes your local cookies, punch in your zip code on the Girl Scout Cookies site to find your local group and see which cookies they sell.