All Wista 4x5 field cameras allow you to change the orientation of the back. But following up on AlanH's post, there's a subtlety of terminology that many people aren't aware of or are confused about.
The metal Wistas, (or at least the late-model ones - VX, SP, RF - not sure about the earlier models) have a revolving back, which means that you can rotate the back while it is mounted on the camera. The wooden Wistas (various DX models) have a reversing back, which means that you have to remove the back from the camera, turn it, and put it back on in the desired orientation. But either way, you can switch between vertical and horizontal.