A rare enharmonic Neapolitan harpsichord.  (Enharmonic in this case means there are extra notes per octave.)
True to historic practice, the compass is 4 octaves with a short octave in the bass (from the bottom the notes are C/E, F, D,F#, G, G#, A, Bb, B, etc...)  There are split sharps for D# and Eb, and G# and Ab throughout (except in the top octave where there is a single sharp key for both G#/Ab).  This is an historic disposition for this type of instrument, created to allow playing in a wider variety of keys when tuned to 1/4 comma meantone temperment.  The keyboard is beautifully made with boxwood naturals and snakewood (!) sharps, and carved arcades (keyfronts).
It has handmade wooden jacks and historic tuning pins (not zither pins).
Made about 10 years ago by Jack Peters of Seattle, Washington, to explore the keyboard literature of 16th and 17th century Italy.
This instrument could either be the answer to your prayers for an enharmonic keyboard, or be played as a regular harpsichord (just don't use the extra keys!). To my knowledge,  the following work is needed: It needs a little regulation of the action (a typical periodic adjustment needed to make the keyboard operate evenly and smoothly); the instrument has been stable since it was made, however it has been tuned at low pitch and may need lighter gauge stringing if modern high pitch is desired; the present owner does recall that the builder suggested the soundboard may need additional bracing at some point.
Also the lid is plywood and the buyer may want to replace it to match the rest of the instrument. Note: this instrument instrument does not come with a stand.
NOTE: buyer pays actual shipping/ handling if unable to pickup in the Pacific Northwest region.