simple IC for on-off current detection?
I am trying to identify an IC that can sit in proximity to an
  appliance power cord (120VAC) and simply detect if current is flowing
  or not


Your whole requirement is "hit" by the problem that any current flowing into the load on one wire is also flowing back from the load on the other wire. These two identical currents (passing through identical wires) cause magnetic fields that cancel each other at quite small distances from the load's power cord.

So, the above method is largely unsuitable and unpredictable. 

What people actually do is separate live and neutral feeds and measure the magnetic field produced by only one of these wires. Current transformers or hall effect sensors are used. However, from the sound of it this is not an option to you so good luck in finding a magical method.