Here is my personal instrument. It has been through quite a few changes over the years, but I think I may finally have it in a form that I'm happy with.
The body is an old stainless steel kettle that I found abandoned in the garden. The neck is made from oak of some sort, the nut and bridge are bone that I found on the moors southern England, most likely from a pony. The horn is an antique rubber bulb car horn. The wood under the bridge was scavenged from an old acoustic guitar that I sawed up for another project.
Acoustically, it is really resonant. Bright and warm, with a lot of sustain .