Several ladies do 3T+3T: Sarah Hecken (GER), Laura Lepisto (FIN), Elena Glebova (EST), Alena Leonova (RUS), Ksenia Makarova (RUS), Elene Gedavanishvili (GEO). These ladies aren't always successful with it, though. Sometimes the combo winds up being 3T+2T, or occasionally it gets < on the second jump.
Joannie Rochette used to do 3T+3T several seasons back, but she was only about 50% successful with it. Apparently she gave up on it and instead was working on 3F+3T, but she attempted that just twice in competition, falling on it once and getting the 3T downgraded the other time. Since then her focus has been on skating clean programs, since so many of the other top ladies were getting URs on their 3/3s anyway.