Straightline Collectibles is run by Mark Schneider and sells this customized version of Denix' Colt 1851 Navy that includes the Snake grips which they also sell separately for $39.
Price: $115
The stand alone Snakes come with instructions. I drill holes and use super glue gel. You can take the prongs off with a Dremel tool and then just glue them as well. - Mark Schneider