The Hub

I'm currently using regular StewMac narrow/medium fretwire on this oddball stick dulcimer I'm making. https://www.instagram.com/p/CthLFjSOeSc/?utm_source=ig_web_copy_link&igshid=MzRlODBiNWFlZA== It's diatonically fretted and I'm curious about offering one that's chromatically fretted BUT with the non-diatonic frets clearly indicated.

I've considered something on the fretboard, some kind of inlay (I'm thinking to emphasize the diatonic frets and ignore the bonus ones). But it's also interesting to think about having a dramatically contrasting fretwire of some sort. I suspect gold is likely the only non-silverl option but... ?? In a dream world there's some kind of metal that's black through and through, not just coated. That seems unlikely though.

More generally, what precedent is there in the fretted instrument world for multiple fret colors on instruments? It's like different string colors on harps, y'all! It's a thing!