Herlock Sholmes: Does a player need to do those rolls in order? It can be more strategic if that wouldn't be. Then add the bankroll idea from Michael Coan (You get all extra rolls for the whole course at roll 1, and use them if you want. Therefore there are unlimited rolls per turn, but the total number of extra rolls is limited) and you would have an awesome game.

EDIT:
Or even better, you have unlimited rolls but the player with the least total of rolls wins.