I used to sometimes add soy sauce when I made spaghetti sauce. (These days, I tend to use Worcestershire sauce). More recently, I decided to add soy sauce instead of salt in making polenta. It was a tad darker, but not so much. I thought it tasted better. I thought maybe I was just being weird, but then I saw the Momofuku cookbook recipe for shrimp n grits, which includes adding soy sauce when cooking the grits (which, I know, are not the same thing as polenta, but close enough that you can compare). OK, maybe David Chang is just a weird dude, too, but it makes me feel like my impulse was not that crazy.
I regularly use soy sauce and cheap sherry when making sauteed mushrooms for any purpose. I've added it to onions that were being prepared for French onion soup. I'm always trying to figure out how much I need to cutback on salt in the recipe or if I need to eliminate it altogether. I'm making it up without measurements, so I have to taste as I go.
Do you have any non-Asian dishes that you have modified by adding soy sauce? If so, how did you adjust the salt you would normally use?