Tesla service center said to contact body shops, but the Tesla affiliated body-shops in my area will not sell paint.
What color are you looking for? Tesla doesn't have the MultiCoatRed in stock at the moment or ever (it seems). I picked up the Dr Colorchip kit to fill a rock chip. The paint colors look pretty good, it even has the metallic flakes in it.
I’m going to guess then that all the third party places make a product that’s ‘compatible’ and is as close a match as possible. The touchupdirect kit looks to be $30 shipped while the Tesla one you linked (thanks!) is $55 but has all these other ‘things’ beyond just the paint and clear coat.