In today's (2012-09-14) MMD John Grant asks about retuning the combs
on paper strip musical movements.  Before trying this has he considered
the newer, mostly chromatic movements that are available?

Hendrik Ball offers them from his delightful web site, Grand Illusions,
in the UK:

  http://www.grand-illusions.com/acatalog/30-Note-Music-Box-Set-554.html 

While I'm sure there are other sources as well, Mr. Ball's site he has
a wonderful collection of curiosities and I would hope that others might
support his endeavors.

Just a happy customer!

John Haskey
Bonny Doon, California