I remember a friend had one back in the '70's at a pizza place we hung out at. She handed it to me and I had two Joni Mitchell songs down in no time. She (the friend, not Joni) was pretty impressed. I used to tour as a sound person for a folk group centered around a hammered dulcimer. We played a lot of folk festivals and there were always a lot of the lap style ones around. Pretty easy for people to build and sell along with their other crafts.