I have to say I'm pretty sure I have also seen video footage (amateur) of an A320 almost doing barrel rolls and going vertical. I thought it was over somewhere like Budapest or Poland maybe. Trouble is, I only ever saw it once, and it was a good few years ago now.
Also, I was working with a very experienced A320 engineer at one point, and he spoke to me about the same incident. If only I could remember the details, or his name!