How about baptism and the Lord's Supper?
My first inclination with baptism is to say that baptism by water is the symbol of baptism by the Holy Ghost. If there are two baptisms, what do we do with Ephesians 4:5. I'm sure that there is an explanation for it, but I just don't know it.
As for the Lord's Supper, I do not see a spiritual parallel. I'll think on it for a while.