I have a collection, but I was thinking bass. (Or double bass. Der grosser Kontrabass.) I also play keys, so maybe I could find something local. Or rent.

But flying with miniatures was challenging enough. A double bass is about as maxi as things get without requiring a truck and possibly a crew. (The harpist has it worse, but only just. And she has a sweet dolley, and likely a small truck. I'm thinking about getting a beater truck to move one of those keyboards.)
Ausgezeichnet! Wann und wohin? I haven't been to Germany in decades, so it's past time to head back. And maybe drag my Vietnamese wife along as revenge. (So she can find out what I live through every time we visit family. Though . . . I'm working on that. Slowly.) And also to introduce her to German food and all manner of other loveliness.

I like this idea. I still won't bring my (German) instrument, but I could bring miniatures, maybe, or just myself and we could jam with a public piano or some such.

Or if you're in Berlin I may know a guy with a piano school.