I agree that a PLB is probably the way to go. It works where cellphones don't and it would lead to the safest possible rescue method (i.e. Someone coming back and turning the lift back on.)


Now, if you are hell-bent on rappelling down, there is micro-rappel equipment available out there. I have no experience with it, but from reviews I've read it seems to work (and the same system is sold from many other vendors).

Maxim Micro Rappel System