What do you want in a box dulcimer?
Stephen Seifert's Don Neuhauser TMB is really cool.
I've made a couple of drawings of these things over the last few months, trying to decide what I wanted. Partial frets for sure. I go back and forth on the traditional sheet-metal bridge and nut. I'd probably rent or wangle use of a sheet-metal brake if I went that route. Tin work is hard without the right tools.
I drew this one back in April. It's sort of a trapezoidal PVMB. Would draw something more traditional today, I think. Probably make the box deeper, too.