Post-Production : Software to keep subject in center of frame by Jeffrey M Powers

Does anyone know of software out there that will track a object and keep it in the center of the area I designate? I do a lot of video split-screen (demos with presentations). I follow the speaker 80% of the time on camera 1 (because I have other tasks to do, so I can't dedicate myself to it) while the presentation is recorded with camera 2. I then post-produce, but really cant put the time in to cut the video down from 16:9 to a smaller box with only the presenter in it (to give more space to the presentation). If I had software that would keep the speaker in the center as he moved, I could then render a copy to use and improve my video. With all that said - what is out there? I know I can do some mask-track in Adobe Premiere (I have CS5.5), but not the centering option.