Christian Fittipaldi would be another one , debut season in F3000 he won the title then moved to f1 with lower grade teams to gain experience and then jumped to CART where he had some good success with some wins but never looked like being a title contender.
now it seems his career is in ruins after trying out in the Nascar ranks and from what ive seem failing at that.
P.S great thread this and has brought up some fantastic names , hope we can keep it going