There is an eBay seller here in NC (I am in Wilmington) who must get old sewing machines by the dozens from somewhere. His eBay ID is lalaney. I am sure he can get you the drawer you need.
You will have to identify your cabinet before you can look for the middle drawer, though. Are you a member of TreadleOn yet? You should join if you aren't. It is the best way to learn about old machines, and it is a free list.
Just Google TreadleOn, and you will find it. It is a wonderful resource.