Save template trainings, or copy previous training sessions

I conduct the same web training on a regular basis during peak times of the year. I know I can simply copy/schedule a similar training. I do this all the time. However, that training has fallen off my "Past Trainings" list so I don't have the option to Copy it anymore. It would be nice if I could create my own set of Training Session templates that I can use repeatedly. I can't see if this is possible somewhere.