I bet it'd be worth a whole lot of cash if you did have one.
Han Fey showed an example of a Zeiss Ikon clear plastic euro cylinder in his article regarding cut-away locks... They exist, but I'm willing to bet you have to pull strings to get one.
A cut away is far more realistic on terms of aquiring a practice aid... John Falle, Barry Wells, and Han Fey may be able to get hold of these locks, but I imagine they know some people who who some people...