All of my Cowboy Action pants and "Go to Meeting" Suits are set up for button on suspenders. At a shoot about 20 years ago I had one of the leather workers make me a set that has a removable holster for a derringer. I had a huge belly at the time and the adjusting straps were about 2 feet longer than I needed when I deflated some.
My leather guy drank too much, and his liver quit, so about 4 years ago I found another that made my brother a pair like mine with a J-Frame holster. I was so impressed; I had a holster for a "Lemon Squeezer" made so I'm current in all my fashion accessories!
I have a new in the bag, Hunter brand universal fit set of suspenders that have a removable holster for a "Small Revolver". These are more of a utility suspender than something important, like a wedding or Action shoot. My good pair have been to 15 weddings (including 3 of my 4 kids weddings, and a "Formal Night" on a cruise ship-sans gun)
Ivan