Luthiery Laboratories

To my mind, there are three kinds of "mash-up": functional, constructive, and stylistic.

• A functional mash-up changes the purpose of the base instrument, for example, building a bass on a guitar body. The Uke bass takes this to an extreme.
  
• A constructive mash-up is building a classic design in a different way, for example, substituting masonite and plywood for rare and expensive "tonewoods" ( most of which are in truth neither rare nor expensive, although you can pay a lot for them if you shop in the right places. )
  
• A stylistic mash-up consists of taking features from two or more different instruments and jamming them together. For example, horns on a violin body.

More: Mash-Ups ...