I suppose that a lot of my clients are going for something not quite straight laced at their wedding (although I have done one strictly traditional cake topper and a number of toppers that are a subtle enough to fit in with a traditional atmosphere).
Not all of the brides I work with will be wearing white gowns. The first one I made was for a bride wearing a red dress. My wife wore a blue panel with a dragon print on it for our wedding.
Here is one such topper where the bride is wearing an elegant black dress. And they're defending their new home against the zombie apocalypse.