Hi,
Have you tried a local music store? Or one that sells pianos? There is midwest company that deals with a lot of new, but I think they handle some used pianos and organs too, so they may be worth contacting. Try:http://www.schmidtmusic.com/ They have an 800 number and may be able to stear you in the right direction, or line up a potential buyer too.
:My Friend has a Silvertone two tier organ which we believe is the last model Sears put out some 30 or so years ago. Model No. 4754, Chassis No. 456-47540. She has recently moved and has no room in her new home and would like to sell it. We need info on how to determine fair value of this item.