Lars Hansen wrote: Is there a way to change the default camera orientation for facetime to landscape on my MacPro?...
Not that I know, Lars. FT is not scriptable, and its preferences file does not allow storing default orientation.
Lars Hansen wrote: ... Something I could write in terminal maybe?...
Even if I could find or write some Automator, AppleScript, or Terminal method to change orientation, I cannot imagine any that would be easier to execute than the "⌘R" that changes FaceTime's orientation to Landscape once a FaceTime connection is made.
You may want to join me and send your specific suggestion for this directly to Apple. Use Apple - Mac OS X - Feedback. You are unlikely to get a response, but you can be certain that the responsible Apple people will see your input for consideration in the FaceTime product development process.