Here are some ideas for acquiring rolls:

Subscribe to MMDigest right away.  You will quickly learn a lot about
mechanical music.  Scan the MMD archives (http://mmd.foxtail.com/) for
Mike Grant.  He recuts many Style 125, 150 and 165 rolls.  Reasonable
prices, too.

At one time the Herschell Carrousel Factory Museum in North Tonawanda
(http://www.carouselmuseum.org/) was recutting Wurlitzer rolls on the
original machinery.  Check to see if they still do.

Check weekly on eBay for "band organ."  Rolls show up there at least
monthly.

Join MBSI and the Mid-America Chapter.  At their summer band organ
rally there are used rolls for sale at the mart almost every year.
Even if you strike out at the mart, you will get to closely examine
some Wurlitzer organs and talk to people who have already built
their own organs.

Hope this helps.
Mike Schoeppner, Kansas City, Missouri