At our event last weekend Michael wore his Victorian uniform for the 13th Hussars (pictures of that to come soon I promise) it is a very beautiful uniform and one of my favorites . So in an attempt to look cohesive I wore one of my 1860s dresses and with my dress I wore a sweetheart badge for the 13th hussars. Michael had found it in a box with other miscellaneous military odds and ends and gave it to me. I had been hankering after one for awhile I just think they are so pretty and the idea of identifying yourself by your husband/brother/fathers regiment is such a neat one. A sweetheart badge was traditionally worn by the female members of a mans family while he was away on duty. Different then a standard sweetheart broach it was usually the regimental badge on a pin back. The pin back on mine is broken so I sewed mine to a ribbon and wore it like a little medal :) eventually I want to have one for every regiment Michael collects!
Here are some more examples I found on the Internet, they are usually found on auction sites, I don't know of anyone doing reproductions. And they can be quite expensive when they are guilt, I have even seen a few that we're heavily jewel encrusted :)