I've just finished fitting a pickup to a mountain dulcimer. I made a small plate from an imitation tortoiseshell guitar pickguard. To this I fitted a switchcraft jack socket wired to the ground terminal and the centre one of a 1 megohm mini potentiometer, also fitted to the plate. Next came a cheap 'n cheerful piezo pickup from Maplin (69 pence!) wired across the outer terminals. I very carefully made a slot in the side of the dulcimer furthest away when you're playing it, near the tail, stuck the pickup inside under the playing hollow and screwed the plate on. The slot in the dulcimer body nicely cleared the jack and pot and was just big enough to get a couple of fingers in to stick the pickup in with a heavy-duty double-sided pad. IMHO it looks good with the chrome jack and a low profile knob, and it retains the "open" sound of the instrument. The amp controls can be used to adust the tone to taste and the volume knob on the dulcimer loads the pickup and reduces the risk of feedback. It picks up handling and picking noises too, but that's all part of playing an acoustic instrument. Estimated cost of the bits? - less than £5!