Here's the current version of the Winter Wunder-Bike.
I had to remove the fenders to fit on the big knobby tires, but a hunk of coroplast goes on easy to the cargo carrier to make a low-tech rear fender. It's not as good as the real rear fender. I did have some water up my back, but my new outer layer is wind/waterproof, so no worries.
My current gear includes:
Sweat-wicking layer
Thermal top
Acrylic Sweatshirt
Nylon windbreaker/rain jacket
Motorcycle helmet.
I'm amazed how much warmer the helmet keeps my head!