Who has insulated winter shoes? I have insulated winter road shoes.
What shoes do you have? Gaerne Eskimo - they are SPD compatible
How cold is it where you ride? Northwest Ohio - temperatures in winter are often in the teens - and windy
How much more time can you spend riding in that temp. because of your shoes? My rides get shorter in the winter - but I'm still doing 40+ mile rides
How do they fit (relative to anything, like Sidis, like Birkenstocks, like other cycle shoes, or other street shoes)? They fit like cycling shoes - I went up one size from my normal road bike size
Do you also have extra insoles or booties or other tricks up your sleeve (or your sock)? Yes, I removed the regular insole and put one of those orange "can stand on dry ice" insoles that are sold by lots of people
Anything else? When it's below 25 or so, I may add neoprene shoe covers. I wear either wool ski socks or neoprene socks.

I also use bar mitts to keep my hands warm.

And the rest of my clothes are what you'd expect - winter tights, base layer, several layers (one of which may be wool), and an insulated jacket that is made for cross country skiing but works great for cycling. Oh, and a hat / neckwarmer combination.

Finally, I try to plan my route with the wind / cold in mind.