First person camera on a piston with a simple FT that lets you "look behind" better than the normal one.
Uses Camera's "Look Yaw" variable to move the piston sideways when you look behind beyond a certain point.

Update

Turns out, you can do this with an XML attribute called lookBackTranslation, without using a piston (with a slight caveat).

(Goes into CameraVantage)
lookBackTranslation (X, Y)

Moves your camera position sideways when you look behind (+ 90 degrees sideways?).
You must enable "AutoCenter" for this to work.

First number (X) is how much your camera moves sideways/in X axis.
I'd say somewhere around 0.4 is practical for a 1:1 scale single seater.

Second number, Y, is how much your camera moves vertically at the same time. You can keep it at 0 unless you need it

Here's the caveat. You cannot change when your camera starts moving unlike with an FT piston (it's always 90 degrees), and you must have Auto Center enabled.
Thanks to rexzion for the tips