Matthew Caulfield wrote:
    But maybe that kind of system wouldn't work with something as non-
    resonant as an organ pipe?

I don't agree that organ pipe material is non-resonant, unless it's
made of concrete.  :-)

Bill Chapman pointed out problems caused by "drawing" from one pipe to
another.  To elaborate, if two pipes near each other are pitched suf-
ficiently close to each other, the playing of one of them could be
influenced by the other.  This happens if their mouths or tops are
close together.  A semitone apart is still too close for comfort, which
is one reason for arranging pipes "on sides," that is, alternately on
the left and the right of the rank.  The only way to achieve accurate
tuning is to detune the pipe not playing, spoiling its resonance by
placing something such as cotton wool into the top or the mouth of the
pipe.

John Page,
UK