Where I live, we have many retail stores that specialize in just that. If an old home is being demo'd this company goes out and strips doors, door kits, stairs, spindels, posts, and ......... you name it. This is a treasure for a home wanting this good ole stuff in it and especially after its re conditioned.
I would do a search on Yahoo or Google and see what you get. I am not sure what my search words would be, but maybe, salvaged home interiors, salvaged doors, home demo material,... you get the gest.