There are commercially available ones like that. Generally they're mirror image shots. They're also copyrighted and protected by Prince-of-Darkness level corporations...I avoid those at all costs.
Right now, I've got about 600 skybox images of my own/public-domain to work on though, and I'll be going out more in the warm weather. Mrs. Cobb and the puppies love the rides, and Michigan is a lot prettier when it isn't wintertime.
I'll look through them and see what might work for mirroring. I've just never tried that sort of thing before—you're the first that's asked. That said, I love a challenge.
