I've seen these things called "Chapman Sticks" that are one big 'pole' of ironwood, which is a super-hard wood. The fretboard runs all the way down to the bridge because you basically fingertap with both hands; it has like 10 strings and can do bass/treble parts simultaneously. Trey Gunn, who played with King Crimson for a time, was known for using one... and I think Sting and a few others have noodled around with one before. But... as you can imagine... it's very staccato.