There's an old adage that says that necessity is the mother of invention. I would put it to you that laziness in the mother of invention. Well, maybe sometimes.
I have a pair of good overalls that are flannel-lined that Steve bought me last fall; they are for wearing in public. He bought me a pair of fire hose cloth work overalls at the same time, but I didn't think to see if they had a flannel-lined version. However, I quit worrying about buying flannel-lined overalls for working because I've taken to wearing my pajama bottoms under my overalls. I did it one morning because I was too lazy to strip off my jammies and put on a pair of underpants and then climb into my overalls. What a happy discovery!
All I can say is I highly recommend jammies under overalls. Nice and toasty.