Actually I know two body shops in my area that I very highly regard and I really hoped they could do the work. But your post and other messages I've seen has led me to conclude that Tesla, given the special skills require to work on the Model S, takes it very seriously when they certify a shop and that I should use a Tesla approved shop.
I think that's smart, but don't be afraid to ask questions and check on their reputation and that they don't have a confrontational attitude towards your insurance company. They should be happy to let you see their operation as well.
You should end up with an invisible repair with everything just as it was before the mishap.