Here's one of my main bikes. Mainly intended for randonneuring but since it has fenders and lights and is comfortable I often end up commuting on it.
The fenders are really old --from a German bike from the 1950's-- and I didn't want to punch more holes in them, so I cut the mud flap with a long tang hidden inside the fender and held on by the rivet up near the fender stay. If you look closely you can also see the front mudflap in the photo. It is so long it actually scrapes the ground sometimes (mainly when wet). All in all a success.