That being said. She's what... in her 40s? Maybe 50? I don't know her age but you cannot teach an old dog new tricks when it comes to something as natural as the voice. She may tone it down temporarily but it's not going to last. You can teach Jack Benny to walk like a man and it will last perhaps for a show or two but it wont be long before he's walking like a female again.
I say take a chance and BE YOURSELF
Still in awe how many do not understand the difference between speaking outdoors and indoors. All the times Palin has been criticized for her voice? Outdoors. You can even pull up old interviews of Palin before the nomination and her voice is very level. Heck, her voice after the election was pitch perfect INDOORS. See the Perry hosted Governor’s Convention when she answered questions.
If you don't think that this is possible, I suggest you compare Hillary Clinton's voice in the 1990's with her voice today. She has probably had the best training that her hollywood buddies can give her. She used to be really shrill. Her message hasn't improved, but her voice has.
Others have done it at her age. One of Margaret Thatcher's unusual accomplishments was retraining her voice. Apparently, she once had an accent that was a real deal breaker for a politician, but overcame it through voice training.
I was voice trained in my fifties to do radio work. Your comment about an old dog is just not true.