Looks like there is a bridge to nostr (see below) and I've heard about someone doing a BTC transaction over LoRa (not sure if it was meshtastic), but I haven't seen the code. It should be reasonably straight forward to whip up though.
Discussion
Were you thinking about Nutband nostr:npub16v82nr4xt62nlydtj0mtxr49r6enc5r0sl2f7cq2zwdw7q92j5gs8meqha? Cashu Ecash over Reticulum
No, but I'm going to stash this one away in my notes in case I want to dig deeper. Thanks for sharing!