There are at least 2 cases that are of the right vintage. One is the "lemongrass" case, the other one is a "beige" plastic case. The plastic one will need an adapter, because by default it covers the foot pedal plug.
No affiliation to any of these sellers, just the best pics I could find without tearing up the sewing room.
Lemongrass:
http://blog.sew-classic.com/2009/03/...ne-review.aspx
There are 2 sizes though, be careful. We have one of each here. The 301 case is smaller.
Plastic:
http://www.ismacs.net/singer_sewing_...g-machine.html
There's also this one, I've never seen it in real life though:
http://m.bonanza.com/listings/SINGER...CASE/102712921
The adapter is the fleshy colored piece in the picture in this thread:
http://www.quiltingboard.com/vintage...m-t184324.html