So it turns out that Czech bluegrass is a thing. Possibly quite a big thing. (there are a lot of Czech bands)
I’m listening to Křeni right now, and they’re really quite good. It’s fun to hear a pretty distinctly American style of music in a non-English tongue.
There’s also G2 Bluegrass Band (Swedish), Meantime (Slovak, and I’d actually heard ‘em before), Four Wheel Drive (Norwegian), and Rawhide (Belgian)