A toggle switch labeled, "EFI/carb"

[sfg]

In my first post I mentioned my idea of using a port injection setup 
as primary, and a carb as a secondary (backup) fuel system on the 
same motor.

Has anyone used a carb as a throttle body, by either using the TPS found
in some carbs, or by otherwise fitting a potentiometer? I would
appreciate any ideas. In particular, on the implementation of IAC in a
carb-as-throttle-body configuration. 

This unorthodox idea stems from experiences with GM ECU failure, using 
my 4x4 on expeditions in the Mid East and Africa. Yes, modern ECUs 
are durable, but having a backup fuel metering system, which does 
not rely on any electronics is important to me. Better to throw a 
switch labeled "EFI/carb", keep the group moving, and tinker after 
sundown in the event of a FI malfunction.