I searched for quite a while for Kahler Bass tremolo bridges - I found a few references, so they exist, but I could not find a site for Kahler International. I did find the following site that offers setup for Kahler-equipped basses and is also a distributor for Kahler:
http://www.wilddutch.comI also found the following address for Kahler (on a Brian May fanpage, accuracy is unknown):
Kahler International
P.O. Box 6200
Anaheim, CA 92816
United States of America
Telephone: +1-(714)-239-1550
Fax: +1-(714)-239-1552