Seshomaru had better be doing Dullindal! That guy's VA (can't remember his name either...) is one of the better English VAs out there. He was absolutely fantastic as Treize Kushrenada in Gundam Wing and his Seshomaru is easily the best voice on dubbed Inuyasha. He's got a calm, serious and brooding voice that works perfectly for 'mature, no nonsense' characters.

edit - sorry, i realise that this topic is getting woefully off-topic... I guess it's got alot to do with the fact that we have very very little facts on the Bleach dub to discuss... and speculation can (and will) include every wild thought out there...