Mad Scientist Strain
Mad Scientist Strain isn't a fourth class. It's a mutation that can appear in Steady State, Studio Class, or Electric when a question pushes the build somewhere outside the normal path.
A mutation might change the scale, string count, body construction, hardware, or the entire way the instrument is expected to behave. Some happen once. Some work well enough to become methods. More than one mutation can show up in the same specimen.
The list so far
MULTISCALE
Different strings get different scale lengths, allowing the instrument to balance tension and feel across the neck instead of forcing every string to live under the same geometry.
HEADLESS
The tuners move away from the headstock and the conventional head disappears. Less mass at the far end of the neck, different balance, different hardware, and a completely different silhouette.
DEEP SCALE HYBRID
An instrument pushed into a different register or scale relationship far enough that the usual labels stop being very useful. The octave and treble-octave builds live here: familiar string relationships shifted into a different physical and sonic range.
SEVEN-STRING
One more string changes more than the neck width. Scale, spacing, pickup choices, balance, and the whole physical relationship with the instrument have to follow it.
FIVE-STRING ACOUSTIC
An acoustic built around five strings because six wasn't the question being asked. String spacing, loading, voicing, and the rest of the instrument are allowed to follow from there.
CHAMBERED ELECTRIC
Material is removed from inside an electric body to reduce weight and change how the body behaves without turning it into a conventional hollow or semi-hollow instrument.
This isn't the complete list. It's the list so far.
A few ways this can stack
CLASS — Steady State
ARCHITECTURE — Synthesis
MUTATION — Five-String Acoustic
SPECIMEN — [existing five-string]
CLASS — Studio Class
ARCHITECTURE — Oscillation
MUTATION — Five-String Acoustic
QUESTION — What does the more refined version of that experiment become?
CLASS — Steady State or Studio Class, later
ARCHITECTURE — Synthesis
MUTATIONS — Multiscale + Deep Scale Hybrid
QUESTION — [the multiscale octave idea]
CLASS — Electric
ARCHITECTURE — Ionization
MUTATIONS — Seven-String + Multiscale + Headless
Mad Scientist Strain isn't about making something strange for the sake of being strange. It's permission to follow a useful question farther than a normal build requires.