I understand your sentiment. But then I watch some of those Broadway.com backstage videos of actors in their dressing rooms, showing items that people have sent and I wonder what happens to it all. Actors are gypsys, never staying in one spot (i.e., dressing room) very long, and for some their housing is ever-changing, too, so I assume most have learned the art of minimalism and traveling light.
As with stagedooring or passing an actor on the street and striking up a conversation, we may feel they are our best friends -- live theater adds to that feeling -- and we give gifts to friends, so it makes sense, right? But they're not.
I love the idea of a brief, thoughtful handwritten note on some simple stationary. I work in philanthropy, a field where a kind, genuine note can touch someone's heart far more than a tangible gift.