BTW
Every court that has ruled that Terri "wants" to die, has based that on hearsay evidence from her husband, his brother, and the brother's wife. That's not much to kill someone on, and it wouldn't be admitted in a criminal court.
Aside from this, there's nothing. You can call in two million "experts," and how would they be able to look at someone and say, "that person doesn't want to live."
And for God's sake, I hope that you don't consider a poll of how many people would want to die in Terri's condition as any sort of legal input to the case.