I think that Chalmers has been fairly clear about what he intends to be removing from the z-world. In the Consciousness Online Conference he put it this way:

    The arguments are just using “phenomenal consciousness” the ordinary way: someone is phenomenally conscious if there’s something it’s like to be them.

    (You can find the Consciousness Online Conference and the discussion I'm referring to here.

I guess you might think of what zombies do as akin to sleep walking (I'm not sure if the subconscious activity or what not that causes such behavior gets lumped in when we talk about being without consciousness, but it doesn't seem like it should). Really then, I don't see any serious difficult in conceiving of zombies; perhaps you're trying to conceive of being a zombie, which I admit would be rather difficult. I don't think that any discussion of our understanding of our own mortality or anything like that helps to do any explaining of what exactly consciousness is. Instead, it seems to only be a part of a list of things that human consciousness is capable of accomplishing. I think that the line that Dave Beisecker brings up in the Consciousness Online discussion is perhaps one that you might be sympathetic toward or in agreement with, and I think it may be a good way of handling the zombie argument. Instead of trying to argue that the idea of zombies makes no sense because we lack any clear definition of what we mean when we talk about consciousness, because Chalmers does make it clear what it is he's talking about, I'd argue that this "ordinary" understanding of consciousness as something it's like to be that thing either isn't gotten as cheaply as Chalmers might want us to believe, or that this ordinary notion of consciousness doesn't get you so far and really has little or no place in the overall discussion of the nature of consciousness.