In the UK, Peter Jones (a UK entrepeneur known mostly for his appearance on Dragon's Den) has the right idea. Although his wealth is estimated at about £220 million, he has stated that he won't give it to his children, instead he has offered to match what they earn (so, if they earned £30k then he'd give them £30k).
'My children won't get large chunks of cash, no. I've set up an arrangement which gives them something called match-funding. When they finish full-time education and start to work, whatever they earn, they will get the same again. Every year for the rest of their lives the trust will double their income.'
And, if they are performing what he considers to be a "worthy" occupation (I seem to recall he gave doctor or nurse as examples) then he would double that gift.