None that I know of, but I am sure there would be a market for this... at the very least, on routes which are flown multiple times per day then it should be possible to designate some of the flights as "min age 12" or something.
Why not have a complete service child free? Charge a 10% premium for that flight and no super discounts or perhaps no discounts at all. With suitable publicity it would not take long to see if the numbers justified it.