I can't recommend a particular one ( I do remember having the most delicious one in Rainforest Cafe but that was many years ago and I can't remember what it's called ) but you can buy cocktails sans alcohol wherever you can buy the ones with.
Have you checked out the Cocktail Thread here? There may be some recommendations on it.
hi i dont drink alcohol and have tried a couple in blue lagoon i had the celebration cocktail which came out surrounded in dry ice which looked really good. i had one in rainforest cafe think it was called a rainforest ricky. a couple in cafe mickey and tried 3 different ones in sequoia lodge. they were all really nice and had different fruit juices you can also get childrens cocktails makes a nice treat