as far as the printing of playable instruments is concerned, at present the size of printable objects is limited by the travel of the printer's axes. average size on affordable 3D printers is 8" x 8" x 8". An 8 inch long instrument would be a toy.

But people will eventually get clever about designing small components that snap or screw together to make items that are bigger than the volumetric range of the printer

Models for Items like capos are already available.