Not officially confirmed, but there was solid evidence in the Art of Skyrim coverage, so the general consesus is that they are back under the Two-Handed skill.
... OK... really?
I'm not sure that shield bashes are gonna deal damage, they'll just stagger the opponent.
Moar liek swagger amirite?
I was sooo gonna roll a Bosmer Spell
shield who's routine going to be more or less like this:
>throw weakness to frost
>frost spell
>spam fire spell
>dual shield bash when they're getting too close (or if dude's a Nord) then promptly back da fuk up like real quick
>frost spell again
>fire spell (holding button down a.k.a.
roast 'em good)