SMC is in the process of building 300 new axle clutch discs. I estimate that they will be available to racers in approximately 30 days. When they are ready, they will be listed on the SMC online store. http://www.kartclutches.com/store/
Other axle clutch parts might be manufactured if there is sufficient demand. Please email requests to firstname.lastname@example.org and type “axle clutches” on the subject line.
Also, John Scavuzzo has a large supply of links. Perhaps someone can supply his contact information.