I just saw a cool adapter on ebay for a Featherweight. Check this one out-it's called a Singer featherweight foot pedal adapter to use with the original foot.
http://www.ebay.com/itm/Singer-Feath...item51bea0014d There are multiple types of foot pedals designed to use with the Featherweight available through ebay as well. Most are in the same price range as this adapter: $35-$45.