I wouldn't be surprised, but I haven't heard anything solid. Taurus' website doesn't get updated that often, so it tends to be pretty useless when it comes to keeping up on their latest stuff. My local shop seems to get their hands on the newer Taurii when they come out- they had some of the Ti frames PT1911s the other week, and I hadn't heard word one of those.
A Ti framed PT1911 in 4" would be REALLY nice- I would not be surprised to see them come out soon, that seems like the logical next step for them. But I have no idea when that would happen.