There's a messianic pastor in this area that encourages multiple baptisms. If you feel like sin in your life is getting in the way of your relationship with God he encourages another baptism. I'm not sure where I stand on this. Haven't given it a whole lot of thought.
Can't say that I see anything wrong with it, understood symbolically, of course.
Our church practices foot washing on Passover. Part of it's symbology is of a mini-baptism, to wash away the sin we've trodden in the last year.
John 13:10 Jesus saith to him, He that is washed needeth not save to wash [his] feet, but is clean every whit: and ye are clean, but not all.
John 13 is a great chapter for teaching about spiritual uncleanliness and humble service...