In contrast to "traditional" mountain dulcimers, which have diatonic fretboards, it's also possible to build chromatic dulcimers. I often jokingly call mine Martian Dulcimers, as the chromatic fretboard is sometimes seen as an space invader in the mountain dulcimer world — and also because I first used them on the Twang Darkly album Martian Archaeology. I've built both acoustic and electric chromatic dulcimers.
Sometimes, commentary in the online dulcimer community implies that the chromatic dulcimer is best suited for what is termed "chordal playing" (as contrasted with what folks call "modal playing"). From my point of view the chromatic dulcimer is a remarkably well-suited and extremely versatile tool for modal music, however.
That is, you can totally use a chromatic dulcimer to channel your mountain-folk-world modal mojo! In fact, the full fretboard provides access to a wider variety of modal concepts than the the seven "Western modes," an extended palette which I leverage with my trio Twang Darkly.
My electric gourd is essentially a chromatic dulcimer set up to be played with a slide.