[gorgarath]

If you have an unlimited data plan, you might want to look into Dashwire. I believe if you have it set to sync automatically, it updates the text messages as you send/receive them. (Or at least shortly after anyway.) And you could view them on the dashwire page. Not sure if that would be something that would work for you or not.

EDIT: Actually, nevermind. I just checked my Dashwire and it didn't sync (when I manually told it to since I don't have it set to automatic) my sent text, apparently because I didn't have the Q set to save sent messages. After turning that on, it did sync the test message I sent. So you're still in the position of needing to keep her from disabling the saved sent messages. Advantage is, if you can keep her from disabling it, even if she does go in and delete the messages, if dashwire is set to automatic, it should already have saved a copy on the dashwire site. Of course, she could always kill the dashwire application.