I believe that your question was answered already. :-) That said, if you do find doors, be sure that they are solid wood as opposed to veneered. Veneered doors will fail after the first couple of wet/snow seasons - not too mention sun damage.
You can try Recycle Ann Arbor on South Indutrial. The doors there are newer (perhaps) and cheaper (perhaps also) but I would not use a venerable door to leave it outside to rot.
Materials Unlimited, they are my favorite, .I not only have old school doors, they have lots of really great stuff from around the globe,and different eras. Also, they have an awesome staff, and have a few cats to help you if you need it,. I recommend this place to every one, have a great day
You'll definitely be able to choose from many different doors etc at this place
They have hundreds of doors!
Thanks! Your answer is awaiting moderation.