Are you saying you're a personal trainer of sorts? When you're at the top, who's going to train the trainers, is it lonely up there?
I don't think you're talking about motivating entertainment are you, like music while working out?
Are you looking for workout partner?
If you're looking for a serious challenge to motivate you, why not run if you are not already? Running is it's own world of motivation and you either do it or you fail at it. It takes a lot of will power to be able to do any distance, but once you're able to do 2-3 miles and up from there, your motivation can really take off since you feel so good about your ability and fitness at that point!