I have used some great folks, California Belting, for many years.  We
use a 22-foot leather drive belt on the Griffith Park Merry-Go-Round.

  California Belting and Leather Company
  South El Monte, CA 91733
  tel.: 1-626-444-8155
  John Olivas, proprietor
  http://www.californiabelting.com/ 

California Belting and Leather Company is a small but extremely good
company specializing in small orders.  They also make our safety seat
belts.  I usually just call John.

We never tried a synthetic material for our drive belt but we did use
it once for our seat belts and they wore out too quickly and looked
too non-traditional for an 80-plus-year-old carousel.

I don't know the costs.  The last time I ordered a drive belt it took
them awhile to find good leather as most is now coming from Mexico and
is too thin for my hard use.

Good luck,

Rosemary West - Griffith Park Merry-Go-Round, Los Angeles

 [ The Stinson Model 87 band organ plays at
 [   http://www.youtube.com/watch?v=4f8eOTeMsZ4 
 [   https://www.youtube.com/watch?v=RTuSEBae_zg 
 [ The 1926 Spillman carousel is described at
 [   http://www.laparks.org/dos/parks/griffithpk/mgr.htm 
 [ -- Robbie