lira, concerning the shield question, there IS a particualr BF monster that drops almost exclusivley shields (most all magical at the higher levels), but i'm sorry, i don't quite remember which monster it is. i believe that it is the red deathknight foe that drops these.
here are a couple shots of shields -
finishing shield and
early shield you'll notice that both these pics were from the end of act II!
good luck. shields are mostly a monster drop, so don't feel unlucky not finding them available at the various merchants.
