Some folks from The RPF have been passing this around: a guy built a working acoustic version of Spock's lyre. I've seen some functional version before, but they've always been electronic and used electric guitar amps to make the sound. Be sure to listen to the MP3 of him playing it; I'm really surprised at how good it sounds, especially given the simple construction. (By the way, does anyone know who designed the lyre? Did they have any musical trianing such that the string legnths and body shape would actually work as an instrument?)
Surprisingly good sound for the minimal planning he describes being involved in the process. I'd love to see what could be done by someone with some instrument-making know-how (though there's something more in his design than can be explained simply by intuition) and some solid maple for the frame and soundboard instead of plywood.