Thanks for the reply. What I am really looking for is not a mirror as much as an additional camera to replace the mirror, not picking a different eye to mirror. As far as I understood, the mirror is actually rendered separately (different aspect ratio and resolution)? Ideally I would be looking to render on the screen a camera view from a fixed position in the virtual space (without having to resort to the in-game external camera - I would still like to have the same cockpit view in the HMD.
Oh, and I probably should have mentioned, I am using a Valve Index so the software is SteamVR.