yeah, that was my plan -- sacrifice about a half inch of dead travel in the accelerator so that I can still shut it off.

actually, now that I think about it, I'll need a return spring anyway, and that will take up the extra slack which I allow for the emergency stop. so when the emergency stop is pressed, the pedal will actually come up about half an inch, but no one will be in the cab to see it

I had thought about using the cruise control cable slots, but they are so far down on the lever arm that they only move about an inch for the entire throw of the accelerator, so I would either have to mount my cable way down on the gas pedal arm, or my gas pedal would be very sensitive.

thanks for all the advice guys, its really helpful to get all of these perspectives to consider.

oh, and my dash does in fact have a choke knob, so I think I'll use that to add a shutdown cable.