The long circular glass-like shades on the bedroom and bathroom lites were cracked in our 1961
Safari and needed replacement. We couldn't find them anywhere. However we found a material that can be used to make almost identical replacements and that work equally as well.
We bought an acrylic flourescent ceiling panel from Home Depot, cut out a right sized piece using a skill knife, and while heating it evenly with a heat gun (wearing gloves), bent it into the right semi-circular form and shape.
(there's a picture of the old lamp shade in our photo album. We'll post a picture of the new shade as soon as we take one)