The results of my query about vendors of audiobooks on CD -- and thank you very much to all who replied!  I've included some relevant comments with each.

MicroMarketing is a favorite, 4 votes with a couple of libraries having used their services before.  Advantages: offer replacement discs, use replaceable sleeves & containers, can be ordered with cataloguing & labels.
Midwest Tapes - 3  Also can ship with barcodes & labels.  Complicated website.
Blackstone - 4  Library editions last slightly longer.
Brilliance Audio - 2  Damage easily, can't repair by buffing.
Books on Tape - 1
Ingram - 1
Recorded Books - expensive, but durable ($65-110 each)

--
Margaret (Meg) Converse
Head Cataloguer, Technical Processing
Alpena County George N. Fletcher Public Library
211 North First Street
Alpena, Michigan 49707
megc@alpenalibrary.org
989-356-6188, ext. 19