I've done it a feww times and it looks really cool. I forgot to mention that if you're doing red,white, blue, to have the body primed in white and then just use the red and blue for the dip. I usually use one of those plastic/vinyl wash basins you get when you're in the hospital.
If you decide to spray the paint on the water and dip the body, you have to make sure that you skim the left over paint off the water before raising the body.
The article I referred to was the "Moonwind" and it appeared in the March 1972 issue of Car Model maagazine. I'll bet everybody has a copy of thatlaying around.