lock

Having had a look around without any luck, does anyone know where i can get a reverse gear lockout plate/mechanism. Reverse on mine is left and back. I have seen the Tornado cable mechanism, but would rather a selector guide plate incorporating a reverse gear latch of some form. Any ideas?

I have seen the mod to the exterior door handle to allow you to lock the car via a key tumbler, but has anyone figured out how to also use the interior Miata handle to also lock the door?