Dear MMD's,  Many thanks to Kevin McElhone, Brian Chesters and to Ralph
Schack for their answer or interest to my request about a miniature
Duo-Art roll.  Here is the answer Arthur Ord-Hume gave me and allowed
me to publish for you:

  Now to the miniature Duo-Art roll.  I published two pieces on this
  in "The Music Box" (Journal of the Music Box Society of Great
  Britain).  First (in Volume 9, No. 3, Autumn 1979, page 128,
  together with three photographs) I wrote an article about miniature
  rolls being used by The Orchestrelle Company in London to promote
  certain new rolls.  This particular miniature roll, 28 inches total
  length and 3.5 inches wide, was a Metrostyle promotion.

  Second (on page 198, Volume 9, No. 4, Christmas 1979) I wrote about
  a similar roll for Duo-Art, this one being No. D-355 for Artur
  Rubenstein's selection from Rimsky-Korsakoff's Golden Cockerel.  This
  roll measured 125 mm in paper width and the box is about 6 inches.

  The description of these is that they date from about 1920-1924 and
  they were promotional material representing newly-released piano
  rolls.  They were punched with the theme of the music and, if you
  were clever and could find a way of holding the roll in position
  over the tracker-bar of your piano, and if you closed up the other
  tracker-bar holes with sticky paper, you found that the perforations
  in the promotional roll were the theme of the actual music roll.

  All this is why very few have survived.  They are today quite rare,
  although I know of maybe half a dozen in England, mostly in poor
  condition.

The roll Arthur is describing is similar to the one which will be sold
at auction in Chartres on Sunday Dec. 5th.  A similar example is in the
collection of the Piano Museum in Brentford, near London, according to
what the late Frank Holland told Arthur Ord-Hume in the above cited
articles.

The perforations on the miniature Duo-Art roll are of the same size and
spacing as on the normal Duo-Art rolls, so the miniature roll should be
playable following the instructions given by Arthur Ord-Hume.

Best regards,

Philippe Rouille  (Paris, France)
http://www.cnam.fr/museum/musica_mecanica/