Ogre Magi (and many other D&D critters) do it all the time. Newer versions of that component give a spell failure percentage while in transformed-form.

"Realism" aside... does anybody know what the 2nd Ed rules say about this?

Purely out of curiosity, do the newer vesions also tone down the BMU factor?

Well, till now on none of my spells have failed, what is the chance of failure?

Mu shapeshifter I really strong now...He can tank the whole day and not get hit because of his -14 AC ^_^

But Im still in chapter2 though:P