Wow, this is quite a thread! This discussion started with the proper way to answer a phone when saying "This is she/her." Is there something special about the word "this"? For example, is there anyone who would claim that the following is correct?

"Who is Jane?"
"That is she."

Can we all agree that that question is more properly answered "That is her"? Why, then, does it become an issue when you are referring to yourself with "this"? The two cases seem identical to me.

If these cases are different, why are they? If they are the same, then would anyone argue that the rules of copulative verbs and nominative cases and such would indicate that, when pointing out another person, one should say "That is she"?