Grand Slam Today

I would really like to start playing this wager, but ancient GLD does not offer it yet.
Today you could single the 3 chalks, one which was less than even money, then take the second pick in the 4th leg at 4-1. Turned this $10 horse into a $50 payoff!!!
No its not huge, but if you single the first 3 and play top couple horses in the 4th you're getting $50 on every $4 you bet. Not bad to me.