There really isn't a good "virtual" game equivalent to Rollergirls, is there? Hmm, do developers think there isn't a market for it?
For some reason, this has me remembering the awful game I played years ago based on the American Gladiators (not the most recent one).
I think games based off of off the beaten track sports and obstacle course game shows could be very successful myself. Heck, Mario Party is in a way a simple culmination of those events.