Screening, depending on what you use, will cut down on the beauty of a glass greenhouse and probably cut down on light transmission also. Two ideas...
1. Suncatchers will decorate plus act as "barriers" in the invisible panes.
2. Ever see those decals people put on company car or bus windows that look opaque from the outside, but can be seen through from the inside? Perhaps you could find something similar in an acceptable design and place small pieces on the panes.
