Locational damage is out, so locationally relevant armor would serve no purpose at this point.
Oh, no locational damage in Skyrim, really? (I've not been reading press releases.) That's rather lame, considering older games have already implemented this with no trouble at all. And the fact that Bethesda has already used locational damage in FO3, you'd think it'd be a no-brainer to put it into Skyrim, too.
EDIT: For the record.
In Morrowind, it was %chance to hit. 30% for cuirass, 10% for everything else (L & R pauldron, L & R gauntlets, helmet, greaves, boots). Block skill governs shield.
EDIT2: for nonhumanoids - couldn't they add that data (locational) as attribute tables associated with the model polygons?