I'm with you. I'm probably good for 14 ounces of stuffing all by myself, and that's not including what I'll consume in leftovers!
My wife does most of the side-cooking but I handle the bird and stuffing myself. I do use the mix but I spice it up with things like eggs and celery and fresh cranberries. (Eggs help hold it together so it isn't crumbly.) I also use broth in place of water when mixing it up. In addition to cooking it in the bird, I bake an equal amount in a casserole dish. My stuffing is definitely something you don't want to see a food label on if you are counting your calories.
My SIL asked me to make my stuffing this year.. for 7. It's popular, so I make enough for leftovers. Picked up the fixings yesterday... 3 loaves of bread, veggies, chicken broth, etc: almost $40. This isn't counting spices or others things I already had.
If I showed up with stovetop or something like that, I'd be shown the door! :)