If you ever apply "rare" to sewing machines that one actually kind of qualifies. I don't like the finish myself though.
This fw auction takes the cake for me. A repainted red one for over 3k. When another sold 5 days earlier for under 900. And you can get one custom done by a pro for 800.
http://www.ebay.com/itm/1939-Vintage...item3f174e97a1