This idea just hit me.

Synopsis

Rarity goes on a trip to the museum with Spike and Gabby. Unfortunately, priceless jewels and artifacts began to disappear, and Spike and Gabby are accused as the prime suspects.

It’s up to Rarity to clear both dragon and griffin’s name and catch the real culprit.

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Rarity helping out her little admirer and his special friend, that's sure to be a treat for whoever decides to try it

Sounds like a very promising story. I'd read it in a nutshell.