Hi Chris:
The Hunnicut book that Rob Dab mentions is available from the Patton Museum Gift Shop. I bought mine a couple of years ago when on a military exercise down there... $82.00 US. Well worth the cost as it has piles of info on evolution, contracts, authorised technical changes, etc. Typical US based book... almost no data on other users.
Don't rely on the captions for many of the US photos. The US Signal Corps was responsible for all US army official photography so frequently what is believed to be the caption is in fact the credit. For example: in two of the photos one can see evidence that the units portrayed are artillery. In one, the IHCs are towing artillery pieces and in another the unit badge painted on the side of the carrier is crossed cannon barrels.
Got our White M3 running but still haven't played with our IHC!
Mike