>> Leaving all our various preferences and rants aside, am I correct in
>> that single manuals were much prevalent than doubles, at least until the
>> end of the harpsichord industry? (I base this on what I have read about
>> instruments and iconographic evidence.)
>If I recall correctly, all the surviving (or almost all?) 17th-cent.
>French h'chords have two manuals.
Not quite. There are 2 or 3 singles like the Denis for instance. And,
apart from the Vaudry, virtually al of those 17th.c French were or still
are disposed I 2x8; II1x4, no coupler, even the 1696 Blanchet, in effect
a two singles in one case.
Keyboard Instrument Maker