As long as there is protocol in place to make sure that a doctor does it in a painless manner, and that the patient is suffering from an illness that means that the chances are that most likely (as in 80-90%) that she will die a painful death, then yeah, I'm OK with it.
I feel those that are suicidal deserve to be given time to reflect and proper "treatment". But if a person has no will to live after all resources have been exhausted....why not? They will only prob commit suicide anyway.