I am betting that because of the Queen's obvious affection for her, next tiara outing, Sophie will show up with something new and spectacular from her late mother-in-law's hoard. I really hope so. She deserves it.
I'd quite like to see her in is it called Queen Mary's Sapphire Bandeau? The one Princess Margaret wore a lot? Though I imagine anything sapphire will be left for Kate to match the Big Blue.