What an interesting thread! I too play harp, a 25 string Heartland Lyra, with sharping levers on C's and G's. My next one is going to have them on the B's too, because lots of the music I'm learning is in the key of F. I'm taking lessons from a concert harpist, a professor at the university. She's really strong on correct technique. I guess all of her emphasis on "close your fingers completely", lift as you play, elbows up, etc. will make a better harpist of me someday, but for now it's terribly hard to concentrate on playing the correct notes, let alone all of the technique. Yes, I'm just a frustrated beginner.
I do also play hammered dulcimer... much easier, I must say. And yes, I have a plucked psaltry, and a couple guitar zithers. Actually, one of what I thought was a guitar zither... has double strings instead of single strings per note, and the instructions say that it was played with a flexible hammer... which did not come with my instrument (which I located at an antique shop).. wish I could find one of them.
Have any of you played a Hawaiian tremeloa? It must be my "weirdest" instrument yet. Strings in chord clusters at the bottom, but across the top is ONE string... this is hard to describe... and attached to a hinged bar, there is a pick and a small bar, side by side, which "fret" the string, and pluck the string... giving a hawaiian guitar sound to this string as it's played. Yep, pretty weird.