I live in a house with metal siding, sort of the mother of all Faraday
cages, so AM reception is terrible for any station whose transmitter
is more than 10 miles away. Reception from car radios is acceptable to
excellent. There seems to be something about car radios - perhaps they
have special circuitry to reduce or eliminate antenna directionality.

So what I am going to do is build a little "doghouse" to place outside
containing: 1) A car radio featuring an IR remote (available for $120
or so), 2) a 110 VAC - 12 VDC transformer, 3) one of those X10 800
Mhz audio/video beamers, and 4) a Radio Shack infrared remote extender
(converts IR to an RF signal then back to IR). Then I can wirelessly
receive the AM signal inside and change frequencies. So what I'm
wondering is:

1) Anyone with a better idea for the overall problem?

Would just mounting an outside antenna and feeding a cable into the
house be too simple?