I know next to nothing about guitars. Double neck guitars are similarly mystifying.
Nonetheless, today’s invention is a double neck guitar -with only one neck.
Actually, this would effectively be two guitars, with the required different properties, placed back to back and melded together.
The combined neck would need some extra reinforcement and, in order to allow the fast change between instruments which is the main reason for double necks, the strap would have a bearing at each end allowing the instrument to be rapidly spun about its longitudinal axis.