According to Father Kodak  <dont_bother@IDontCare.COM>:

    How much good would that do?  Most lenses have a relatively
small focus travel -- especially compared to the travel of the bellows
itself.  Only some of the old *real* macro lenses have enough travel to
make some difference, and those which I have handled were not autofocus
either.

    And once you get to near a 1:1 ratio, attempting to focus by
moving the lens is an exercise in frustration.  You move the lens to
define the magnification ratio, and then move the camera and lens as a
unit back and forth relative to the subject to find final focus.

    You put them aside The zoom lenses are probably poor choices for
bellows mounting anyway -- unless you can make a spacer between the lens
and the bellows which allows you to control the position of the
stop-down lever in the back of the lens, as you are lacking all other
control.  (Unless some of the more recent bellows assemblies have
provisions for moving the electrical connections, and the stop-down
coupling through the bellows assembly.)

    Certainly the old Nikon Bellows-II (which will also fit on the
D70 with the same caveat about rotating the orientation of the mount
prior to assembling to the camera).  (The corner of the rear standard
still bears on the underside of the pop-up flash housing, but not enough
to prevent mounting or to damage anything.)  A little careful filing or
grinding would clear that totally, but then it would need to be
re-painted with wrinkle-finish black enamel -- and to get the same
finish, it should be baked, which would mean removing the actual
bellows.

    Enjoy,
        DoN.

I appreciate your concern--I probably wouldn't have mounted the bellows in
the first place had I known that it was not "allowed". Sometimes ignorance
is bliss--and I understand that you meant that the rotation of the bellows
could not be the reason that it was blacklisted. I have been using the PB4 &
5 happily for years, and just recently picked up the PB6 for $50 with the
double cable release (couldn't resist at that price) but have not used it
much, so I didn't remember that it too needed to be rotated.

But...

After your post, I had a very close look at the mounts of both the PB5 and
6. They are identical. I even measure them with my digital vernier calipers.
Absolutely the same: no extra bulges or flanges or slots or channels. I
mounted both on the D200--the viewfinder clearance is very slightly less (~1
mm) on the older model, but both clear it without a problem. I checked the
clearance of the body at the mount. Likewise no problem. I've checked my CPU
contacts for damage on the camera body, or signs of wear on the inside of
the mount. All is pristine. Unless there is something very unobvious that I
am missing, there is absolutely no problem using the older bellows with the
D200, at least.

To answer Father Kodak, I use the bellows always in manual mode. G lenses,
unfortunately, cannot be used because there is no way to control the
aperture. AF likewise--no connection to the focusing mechanism. Nor does one
get any function (D calculation or EXIF data) that needs to be transmitted
via the CPU contacts. I use the bellows mostly, anyway, with non-Nikon
lenses--a couple of Olympus extreme macro lenses, a short barrel
turn-of-the-last-century 135mm view camera lens. Most of my other non-DX
lenses are manual focus Nikkors anyway, so I don't miss what I never had...

Toby