I noticed that the Crossrock Fiberglass A & F Mandolin case (the model numbers start with CRF 1020 and then the rest of the number reflects the color) fit an RM-1 perfectly! Unlike most F cases, there are not notches cut out for the points, they just made the whole inside bigger - perfect size and shape for an RM-1. I think it is a better case than the original cases because its a little lighter, it has rubber seals so rain can't get in, and comes with shoulder straps / backpack staps for better mobility. Its not a Calton and not really checked baggage worthy, but it is very strong. Check them out if you feel so inclined. I could not add a photo to this specific note so I uploaded it to the Group Photos section.
Interesting. Perhaps if I had one of those I wouldn’t get asked what sort of banjo I had in the case!
Many thanks for the headzzup on the Crossrock for an RM-1. Excellent! Couldn't fit any better. Ryk