I recently made a guitar-bodied archtop octave mandolin. It features a soundboard made with bent staves following the same method as historical viols, and a jointed back made from cherry and sycamore.
The outline is taken from an Epiphone Spartan archtop guitar, scaled down to fit a scale length of 600mm or just over 23".
While this instrument is not for sale, I am currently working on a design for a mandolin with a similar aesthetic and a simpler version of the same construction.