Occasionally 5Dimes will let you parlay the top couple of teams to win the championship in a particular sport. It happens the most with NCAA Football Championship, Golf Futures and Tennis Futures. It is usually the yes/no option on whether a team will win the championship.
I have cashed many parlay tickets with Federer to win a particular tournament tied to my best picks for that week.
5Dimes right now will let you parlay series prices in baseball. Not many books allow you to do this.